1
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Zhou H, Cao Y, Khmelevskyi S, Zhang Q, Hu S, Avdeev M, Wang CW, Zhou R, Yu C, Chen X, Li Q, Miao J, Li Q, Lin K, Xing X. Colossal Zero-Field-Cooled Exchange Bias via Tuning Compensated Ferrimagnetic in Kagome Metals. J Am Chem Soc 2024. [PMID: 39039443 DOI: 10.1021/jacs.4c04173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Exchange bias (EB) is a crucial property with widespread applications but particularly occurs by complex interfacial magnetic interactions after field cooling. To date, intrinsic zero-field-cooled EB (ZEB) has only emerged in a few bulk frustrated systems and their magnitudes remain small yet. Here, enabled by high temperature synthesis, we uncover a colossal ZEB field of 4.95 kOe via tuning compensated ferrimagnetism in a family of kagome metals, which is almost twice the magnitude of known materials. Atomic-scale structure, spin dynamics, and magnetic theory revealed that these compensated ferrimagnets originate from significant antiferromagnetic exchange interactions embedded in the holmium-iron ferrimagnetic matrix due to supersaturated preferential manganese doping. A random antiferromagnetic order of manganese sublattice sandwiched between ferromagnetic iron kagome bilayers accounts for such unconventional pinning. The outcome of the present study outlines disorder-induced giant bulk ZEB and coercivity in layered frustrated systems.
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Affiliation(s)
- Haowei Zhou
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Yili Cao
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Sergii Khmelevskyi
- Vienna Scientific Cluster Research Center, Technical University of Vienna, Operngasse 10, Vienna A-1040, Austria
| | - Qinghua Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shixin Hu
- Institute of Applied Magnetics, Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Maxim Avdeev
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Chin-Wei Wang
- Neutron Group, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Rui Zhou
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chengyi Yu
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Xin Chen
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Qiheng Li
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Jun Miao
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Qiang Li
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Kun Lin
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Xianran Xing
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
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Ali W, Xinghan C, Hongxia Y, Zhilong Z, Songliu Y. Comparative study on the magnetic properties of Fe-substituted Co 2Sn 1-xFe xO 4spinel oxides and its exchange bias effect. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:425803. [PMID: 38848727 DOI: 10.1088/1361-648x/ad559c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 06/07/2024] [Indexed: 06/09/2024]
Abstract
Herein, we report the Fe-substituted Co2Sn1-xFexO4(0 ⩽ x ⩽ 0.4) inverse spinel's oxide using the solid-state reaction method. X-ray reveals the single-phase cubic structure with space group Fd3m. With increasing Fe in Co2Sn1-xFexO4spinel oxide, the transition temperature rise. The ac susceptibility at different frequencies also confirms a spin-glassy state at lower temperatures. The strong exchange bias effect appears in the sample having Fe substitution (x= 0.2) under the presence of constant temperature ∼10 K. The high-temperature susceptibility of Curie-Wise fitting shows that the system changes from antiferromagnetic exchange (x< 0.2) to ferromagnetic exchange (x> 0.2).
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Affiliation(s)
- Wajahat Ali
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Chen Xinghan
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Yin Hongxia
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Zheng Zhilong
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Yuan Songliu
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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3
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Chong SK, Cheng Y, Man H, Lee SH, Wang Y, Dai B, Tanabe M, Yang TH, Mao Z, Moler KA, Wang KL. Intrinsic exchange biased anomalous Hall effect in an uncompensated antiferromagnet MnBi 2Te 4. Nat Commun 2024; 15:2881. [PMID: 38570519 PMCID: PMC10991375 DOI: 10.1038/s41467-024-46689-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 03/06/2024] [Indexed: 04/05/2024] Open
Abstract
Achieving spin-pinning at the interface of hetero-bilayer ferromagnet/antiferromagnet structures in conventional exchange bias systems can be challenging due to difficulties in interface control and the weakening of spin-pinning caused by poor interface quality. In this work, we propose an alternative approach to stabilize the exchange interaction at the interface of an uncompensated antiferromagnet by utilizing a gradient of interlayer exchange coupling. We demonstrate this exchange interaction through a designed field training protocol in the odd-layer topological antiferromagnet MnBi2Te4. Our results reveal a remarkable field-trained exchange bias of up to ~ 400 mT, which exhibits high repeatability and can be easily reset by a large training field. Notably, this field-trained exchange bias effect persists even with zero-field initialization, presenting a stark contrast to the traditional field-cooled exchange bias. The highly tunable exchange bias observed in this single antiferromagnet compound, without the need for an additional magnetic layer, provides valuable insight into the exchange interaction mechanism. These findings pave the way for the systematic design of topological antiferromagnetic spintronics.
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Affiliation(s)
- Su Kong Chong
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA.
| | - Yang Cheng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Huiyuan Man
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA, 94305, USA
| | - Seng Huat Lee
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yu Wang
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Bingqian Dai
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Masaki Tanabe
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Ting-Hsun Yang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Zhiqiang Mao
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Kathryn A Moler
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Physics and Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA.
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4
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Malik SV, Dias ET, Babu PD, Priolkar KR. Defect induced ferromagnetism in Mn 3Ga. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:135701. [PMID: 38086084 DOI: 10.1088/1361-648x/ad14c9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/12/2023] [Indexed: 12/22/2023]
Abstract
Ni-substituted Mn3Ga displays a weak ferromagnetism embedded in an antiferromagnetic (AF) phase. Upon field cooling, the alloy exhibits exchange bias and an open hysteresis loop, signifying kinetic arrest at room temperature. For the first time, a kinetic arrest is seen in a compound due to the first order transition of an embedded defect phase. A systematic study of crystal structure, local structure, and magnetic properties of Mn3-xNixGa (x= 0, 0.25) alloys reveal the origin of ferromagnetism in Mn2.75Ni0.25Ga is due to the segregation of a Heusler-type environment around Ni in the cubic Mn3Ga matrix. Upon temper annealing at 400∘C, these local structural defects around the Ni phase separate into a modulated ferromagnetic (FM) Ni-Mn-Ga Heusler phase. A strong interaction between the AF host and the FM defect phase gives rise to exchange bias. The first-order transition of the defect phase seems to be responsible for the observed kinetic arrest in Mn2.75Ni0.25Ga.
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Affiliation(s)
- S V Malik
- School of Physical and Applied Sciences, Goa University, Goa 403206, India
| | - E T Dias
- School of Physical and Applied Sciences, Goa University, Goa 403206, India
| | - P D Babu
- UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC Campus, Mumbai 400 085, India
| | - K R Priolkar
- School of Physical and Applied Sciences, Goa University, Goa 403206, India
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Saritaş S, Çiçek MM, Kavak E, Gurpinar K, Yildirim O, Yuce S, Atakol O, Emre B. Tuning of the magneto-caloric effects in Ni 43Mn 46In 11magnetic shape memory alloys by substitution of boron. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:075801. [PMID: 37931322 DOI: 10.1088/1361-648x/ad0a13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/06/2023] [Indexed: 11/08/2023]
Abstract
In this study, we report the structural, magnetic, and magnetocaloric properties of B substitution on the Mn site in Ni43Mn46-xBxIn11(x= 0.5, 1.0) Heusler alloys. Crystal structure analysis using room-temperature x-ray diffraction data reveals both samples have mixed phases composed of cubic and tetragonal phases. The structural and magnetic phase transition characteristic temperatures are determined using differential scanning calorimetry, isothermal magnetization (MT), and isofield magnetization (MH) measurements. Both alloys exhibit inverse and direct magnetocaloric effects in the vicinity of their magnetostructural transition and Curie temperature (TC), respectively. For Ni43Mn45.0B1.0In11a maximum magnetic entropy change of 25.06 J kg-1K-1is observed at 250 K for a magnetic field change of 5 T.
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Affiliation(s)
- Senem Saritaş
- Faculty of Engineering, Department of Engineering Physics, Ankara University, 06100 Beşevler, Ankara, Turkey
| | - Mert Miraç Çiçek
- Faculty of Engineering, Department of Engineering Physics, Ankara University, 06100 Beşevler, Ankara, Turkey
- REHIS LTCC and Thin Film Department, Aselsan Inc., Ankara 06830, Turkey
| | - Eyup Kavak
- Faculty of Engineering, Department of Engineering Physics, Ankara University, 06100 Beşevler, Ankara, Turkey
| | - Kubra Gurpinar
- Department of Chemistry, Faculty of Science, Ankara University, Ankara 06100, Turkey
| | - Oğuz Yildirim
- Empa-Swiss Federal Laboratories for Material Science and Technology, CH, 8600 Dübendorf, Switzerland
| | - Suheyla Yuce
- Department of Physics, Science and Literature Faculty, Ondokuz Mayis University, Kurupelit, 55139 Samsun, Turkey
| | - Orhan Atakol
- Department of Chemistry, Faculty of Science, Ankara University, Ankara 06100, Turkey
| | - Baris Emre
- Faculty of Engineering, Department of Engineering Physics, Ankara University, 06100 Beşevler, Ankara, Turkey
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6
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Tian F, Zhao Q, Guo J, Kong S, Liu B, Dai Z, Fang M, Zhang Y, Zhou C, Cao K, Yang S. A Giant Exchange Bias Effect Due to Enhanced Ferromagnetism Using a Mixed Martensitic Phase in Ni 50Mn 37Ga 13 Spun Ribbons. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2827. [PMID: 37947673 PMCID: PMC10650613 DOI: 10.3390/nano13212827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
The structure of a material is an important factor in determining its physical properties. Here, we adjust the structure of the Ni50Mn37Ga13 spun ribbons by changing the wheel speed to regulate the exchange bias effect of the material. The characterization results of micromorphology and structure show that as the wheel speed increases, the martensite lath decreases from 200 nm to 50 nm, the structure changed from the NM to a NM and 10M mixed martensitic structure containing mainly NM, then changed to NM and 10M where 10M and NM are approaching. Meanwhile, HE first increased and then decreased as the wheel speed increased. The optimum exchange bias effect (HE = 7.2 kOe) occurs when the wheel speed is 25 m∙s-1, mainly attributed to the enhanced ferromagnetism caused by part of 10M in NM martensite, which enhanced the exchange coupling of ferromagnetism and antiferromagnetism. This work reveals the structural dependence of exchange bias and provides a way to tune the magnitude of the exchange bias of Heusler alloys.
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Affiliation(s)
- Fanghua Tian
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China; (Q.Z.)
| | | | | | | | | | | | | | | | | | | | - Sen Yang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China; (Q.Z.)
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7
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Zhao M, Guo W, Wu X, Ma L, Song P, Li G, Zhen C, Zhao D, Hou D. Zero-field-cooling exchange bias up to room temperature in the strained kagome antiferromagnet Mn 3.1Sn 0.9. MATERIALS HORIZONS 2023; 10:4597-4608. [PMID: 37593768 DOI: 10.1039/d3mh00754e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Zero-field-cooling exchange bias (ZFC EB) has always been a research hotspot for researchers, because it can realize the movement of the magnetization hysteresis loop along the field axis without field cooling, which greatly expands the universality and convenience of the application of the exchange bias effect. Achieving ZFC EB at room temperature is an ongoing challenge. To this end, a design strategy from the sublattice level is proposed, and a wide temperature range ZFC EB up to room temperature with a vertical magnetization shift is observed in the strained kagome antiferromagnet Mn3.1Sn0.9. Magnetic analysis and first-principles calculations reveal that the ZFC EB arises from the strong exchange interaction between the non-coplanar antiferromagnetic Mn kagome sublattice occupying normal Mn sites and the collinear ferromagnetic Mn sublattice occupying Sn sites. This discovery is of great significance for the application of ZFC EB in antiferromagnetic spintronic devices.
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Affiliation(s)
- Mingyue Zhao
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Wei Guo
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Xian Wu
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Li Ma
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Ping Song
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, People's Republic of China.
| | - Guoke Li
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Congmian Zhen
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Dewei Zhao
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
| | - Denglu Hou
- Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
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8
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Averyanov DV, Sokolov IS, Taldenkov AN, Parfenov OE, Karateev IA, Kondratev OA, Tokmachev AM, Storchak VG. Intrinsic exchange bias state in silicene and germanene materials EuX 2. NANOSCALE HORIZONS 2023; 8:803-811. [PMID: 36987577 DOI: 10.1039/d3nh00009e] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
2D magnets have recently emerged as a host for unconventional phases and related phenomena. The prominence of 2D magnetism stems from its high amenability to external stimuli and structural variations. The low dimensionality facilitates competition between magnetic orders which may give rise to exchange bias, in particular in magnetic heterostructures. Here, we propose a strategy for the search of exchange bias state in 2D individual compounds. We track the evolution of magnetic orders driven by the number of monolayers in a system exhibiting antiferromagnetism in the multilayer and ferromagnetism in the monolayer limit. The material, EuSi2, has the structure of multilayer silicene intercalated by Eu. A strong intrinsic exchange bias effect accompanies the dimensional crossover. Comparison with silicene-based GdSi2 and germanene-based EuGe2 suggests the competition between magnetic orders to be a common property of this class of materials that may be useful in spintronic applications.
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Affiliation(s)
- Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Ivan S Sokolov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Igor A Karateev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Oleg A Kondratev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
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9
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Alam M, Chatterjee S. B-site order/disorder in A 2BB'O 6and its correlation with their magnetic property. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:223001. [PMID: 36888997 DOI: 10.1088/1361-648x/acc295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
The disorder in any system affects their physical behavior. In this scenario, we report the possibility of disorder in A2BB'O6oxides and their effect on different magnetic properties. These systems show anti-site disorder by interchanging B and B' elements from their ordered position and giving rise to an anti-phase boundary. The presence of disorder leads to a reduction in saturationMand magnetic transition temperature. The disorder prevents the system from sharp magnetic transition which originates short-range clustered phase (or Griffiths phase) in the paramagnetic region just above the long-range magnetic transition temperature. Further, we report that the presence of anti-site disorder and anti-phase boundary in A2BB'O6oxides give different interesting magnetic phases like metamagnetic transition, spin-glass, exchange bias, magnetocaloric effect, magnetodielectric, magnetoresistance, spin-phonon coupling, etc.
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Affiliation(s)
- Mohd Alam
- Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Sandip Chatterjee
- Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
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10
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Liu C, Zhang H, Zhang S, Hou D, Liu Y, Wu H, Jiang Z, Wang H, Ma Z, Luo X, Li X, Sun Y, Xu X, Zhang Z, Sheng Z. Emergent, Non-Aging, Extendable, and Rechargeable Exchange Bias in 2D Fe 3 GeTe 2 Homostructures Induced by Moderate Pressuring. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2203411. [PMID: 36300686 DOI: 10.1002/adma.202203411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/13/2022] [Indexed: 06/16/2023]
Abstract
As a crucial concept in magnetism and spintronics, exchange bias (ExB) measures the asymmetry in the hysteresis loop of a pinned ferromagnet (FM)/antiferromagnet (AFM) interface. Previous studies are mainly focused on FM/AFM heterostructures composed of conventional bulk materials, whose complex interfaces prohibit precise control and full understanding of the phenomenon. Here, the enabling power of 2D magnets is exploited to demonstrate the emergence, non-aging, extendability, and rechargeability of ExB in van der Waals Fe3 GeTe2 homostructures, upon moderate pressuring. The emergence of the ExB is attributed to a local stress-induced FM-to-AFM transition, as validated using first-principles calculations, and confirmed in magneto-optical Kerr effect and second harmonic generation measurements. It is also observed that, negligible ExB aging before the training effect suddenly takes place through avalanching, pronounced delay of the avalanche via timed pressure repetition (extendability), ExB recovery in the post-training sample upon refreshed pressuring (rechargeability), and demonstrate its versatile tunability. These striking findings offer unprecedented insights into the underlying principles of ExB and its training, with immense technological applications in sight.
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Affiliation(s)
- Caixing Liu
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
- The International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Huisheng Zhang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030000, P. R. China
| | - Shunhong Zhang
- The International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, 230026, P. R. China
| | - De Hou
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
| | - Yonglai Liu
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
| | - Hanqing Wu
- The International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Zhongzhu Jiang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
| | - HuaiXiang Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Zongwei Ma
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
| | - Xuan Luo
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
| | - Xiaoyin Li
- The International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Yuping Sun
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
| | - Xiaohong Xu
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030000, P. R. China
| | - Zhenyu Zhang
- The International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Zhigao Sheng
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, P. R. China
- Key Laboratory of Photovoltaic Materials and Energy Conservation, Chinese Academy of Sciences, Hefei, 230031, P. R. China
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11
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Averyanov DV, Sokolov IS, Taldenkov AN, Parfenov OE, Karateev IA, Kondratev OA, Tokmachev AM, Storchak VG. Exchange Bias State at the Crossover to 2D Ferromagnetism. ACS NANO 2022; 16:19482-19490. [PMID: 36278843 DOI: 10.1021/acsnano.2c09452] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The inherent malleability of 2D magnetism provides access to unconventional quantum phases, in particular those with coexisting magnetic orders. Incidentally, in a number of materials, the magnetic state in the bulk undergoes a fundamental change when the system is pushed to the monolayer limit. Therefore, a competition of magnetic states can be expected in the crossover region. Here, an exchange bias state is observed at the crossover from 3D antiferromagnetism to 2D ferromagnetism driven by the number of monolayers in the metalloxene GdSi2. The material constitutes a stack of alternating monolayers of Gd and silicene, the Si analogue of graphene. The exchange bias manifests itself as a shift of the hysteresis loop signifying coupling of magnetic systems, as evidenced by magnetization studies. Two features distinguish the phenomenon: (i) it is intrinsic, i.e. it is detected in an individual compound; (ii) the exchange bias field, 1.5 kOe, is unusually high, which is conducive to applications. The results suggest magnetic derivatives of 2D-Xenes to be prospective materials for ultracompact spintronics.
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Affiliation(s)
- Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Ivan S Sokolov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Igor A Karateev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Oleg A Kondratev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
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12
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Liu K, Kang C, Tian J, Song Y, She L, Liu X, Zhang W. Canonical Spin Glass and the Anomalous Hall Effect in a Centrosymmetric Ferrimagnet. J Phys Chem Lett 2022; 13:10048-10055. [PMID: 36264631 DOI: 10.1021/acs.jpclett.2c02646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Centrosymmetric ferro/ferrimagnets provide an ideal arena for fundamental research due to their fascinating magnetic and structural characters. In this work, the Co0.8MnSn compound with a single hexagonal phase was successfully synthesized, and the magnetic phase transition and magnetic and electronic properties have been systematically investigated. Interestingly, Arrott plots and normalized magnetic entropy changes derived from the isothermal magnetizing curves may imply the first-order nature of the magnetic ordering transition around TC ∼ 121 K. The AC susceptibility analysis and detailed nonequilibrium dynamical studies (including magnetic aging, rejuvenation, and memory effects) reveal the canonical spin-glass state of Co0.8MnSn at lower temperature. Further, negative magnetoresistance and the anomalous Hall effect dominated by a commonly intrinsic term are obtained. Moreover, the field-dependent AC susceptibility data indicated that complicated and nontrivial magnetic spin textures should exist in the compound. These studies may open up further research opportunities in exploring emergent physical phenomena and potential applications in centrosymmetric magnets.
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Affiliation(s)
- Kai Liu
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
| | - Chaoyang Kang
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
| | - Jianjun Tian
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
| | - Yeheng Song
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
| | - Limin She
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
| | - Xiansheng Liu
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
| | - Weifeng Zhang
- Henan Key Lab of Photovoltaic Materials and Center for Topological Functional Materials, Henan University, Kaifeng475004, China
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13
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Liu T, Yuan Y, Sun X, Tang Z, Cai H, Zhang F, Lu Y, Liu R, Chen J, Huang L, Wei L, Hu Y, Zhang W, You B, Xu Q, Du J. Cooling Field Dependence of Exchange Bias in Mn-Doped Metal- Organic Framework [NH 2(CH 3) 2][Fe IIIFe II(HCOO) 6]. J Phys Chem Lett 2022; 13:7185-7190. [PMID: 35904515 DOI: 10.1021/acs.jpclett.2c01844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Herein, an intriguing exchange bias (EB) effect manifesting itself from positive to negative with an increase in the cooling field (HFC) is reported in the single crystal of Mn-doped metal-organic framework (MOF) [NH2(CH3)2][FeIIIFeII(HCOO)6] (1) by finely tuning the exchange interactions between the magnetic ions. Note that the doping ratio of Mn relative to the total metal ions is about 15%. Negative magnetization and EB below the compensation temperature were both observed in 1, and the EB field (HE) changes its sign from positive to negative when HFC is larger than ∼10 kOe. The abnormal HFC dependence of EB can be interpreted explicitly by a combination of negative magnetization and couplings among the ions of Fe3+, Fe2+, and Mn2+ with varying the HFC. This work demonstrates a tunable EB in MOFs, in favor of designing novel magnetic devices.
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Affiliation(s)
- Tianyu Liu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Yuan Yuan
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Xiaofan Sun
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Zheng Tang
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Hongling Cai
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Fan Zhang
- School of Physics, Southeast University, Nanjing211189, People's Republic of China
| | - Yu Lu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Ruobai Liu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Jiarui Chen
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Linao Huang
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Lujun Wei
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing210046, People's Republic of China
| | - Yong Hu
- College of Sciences, Northeastern University, Shenyang110819, People's Republic of China
| | - Wei Zhang
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
| | - Biao You
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing210093, People's Republic of China
| | - Qingyu Xu
- School of Physics, Southeast University, Nanjing211189, People's Republic of China
| | - Jun Du
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing210093, People's Republic of China
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14
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Albarakati S, Xie WQ, Tan C, Zheng G, Algarni M, Li J, Partridge J, Spencer MJS, Farrar L, Xiong Y, Tian M, Wang X, Zhao YJ, Wang L. Electric Control of Exchange Bias Effect in FePS 3-Fe 5GeTe 2 van der Waals Heterostructures. NANO LETTERS 2022; 22:6166-6172. [PMID: 35912475 DOI: 10.1021/acs.nanolett.2c01370] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Manipulating the exchange bias (EB) effect using an electronic gate is a significant goal in spintronics. The emergence of van der Waals (vdW) magnetic heterostructures has provided improved means to study interlayer magnetic coupling, but to date, these heterostructures have not exhibited electrical gate-controlled EB effects. Here, we report electrically controllable EB effects in a vdW heterostructure, FePS3-Fe5GeTe2. By applying a solid protonic gate, the EB effects were repeatably electrically tuned. The EB field reaches up to 23% of the coercivity and the blocking temperature ranges from 30 to 60 K under various gate-voltages. The proton intercalations not only tune the average magnetic exchange coupling but also change the antiferromagnetic configurations in the FePS3 layer. These result in a dramatic modulation of the total interface exchange coupling and the resultant EB effects. The study is a significant step toward vdW heterostructure-based magnetic logic for future low-energy electronics.
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Affiliation(s)
- Sultan Albarakati
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
- Physics Department, Faculty of Science and Arts, University of Jeddah, P.O. Box 80200, 21589Khulais, Saudi Arabia
| | - Wen-Qiang Xie
- Department of Physics, South China University of Technology, Guangzhou510640, China
| | - Cheng Tan
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Guolin Zheng
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
| | - Meri Algarni
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Junbo Li
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
| | - James Partridge
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Michelle J S Spencer
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Lawrence Farrar
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
- Department of Physics, School of Physics and Materials Science, Anhui University, Hefei, Anhui230601, China
| | - Xiaolin Wang
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, New South Wales2500, Australia
- Institute for Superconducting & Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Yu-Jun Zhao
- Department of Physics, South China University of Technology, Guangzhou510640, China
| | - Lan Wang
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
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15
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Bersweiler M, Bender P, Peral I, Pratami Sinaga E, Honecker D, Alba Venero D, Titov I, Michels A. Magnetic nanoprecipitates and interfacial spin disorder in zero-field-annealed Ni 50Mn 45In 5 Heusler alloys as seen by magnetic small-angle neutron scattering. J Appl Crystallogr 2022; 55:713-721. [PMID: 35974732 PMCID: PMC9348882 DOI: 10.1107/s1600576722006355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/16/2022] [Indexed: 11/10/2022] Open
Abstract
Shell ferromagnetism is a new functional property of certain off-stoichiometric Ni-Mn-In Heusler alloys, with a potential application in non-volatile magnetic memories and recording media. One key challenge in this field remains the determination of the structural and magnetic properties of the nanoprecipitates that are the result of an annealing-induced segregation process. Thanks to its unique mesoscopic length scale sensitivity, magnetic small-angle neutron scattering appears to be a powerful technique to disclose the microstructure of such annealing-induced nanoprecipitates. In this study, the microstructure of a zero-field-annealed off-stoichiometric Ni50Mn45In5 Heusler alloy is investigated by unpolarized magnetic small-angle neutron scattering. The neutron data analysis reveals a significant spin-misalignment scattering, which is mainly related to the formation of annealing-induced ferromagnetic nanoprecipitates in an antiferromagnetic matrix. These particles represent a source of perturbation which, due to dipolar stray fields, gives rise to canted spin moments in the surroundings of the particle-matrix interface. The presence of anticorrelations in the computed magnetic correlation function reflects the spatial perturbation of the magnetization vector around the nanoprecipitates. The magnetic field dependence of the zero crossing and the minima of the magnetic correlation function are qualitatively explained using the law of approach to ferromagnetic saturation for inhomogeneous spin states. More specifically, at remanence, the nanoprecipitates act magnetically as one superdefect with a correlation length that lies outside the experimental q range, whereas near saturation the magnetization distribution follows each individual nanoprecipitate. Analysis of the neutron data yields an estimated size of 30 nm for the spin-canted region and a value of about 75 nm for the magnetic core of the individual nanoprecipitates.
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Affiliation(s)
- Mathias Bersweiler
- Department of Physics and Materials Science, Université du Luxembourg, 162A avenue de la Faïencerie, Luxembourg L-1511, Grand Duchy of Luxembourg
| | - Philipp Bender
- Heinz Maier-Leibnitz Zentrum, Technische Universität München, Garching D-85748, Germany
| | - Inma Peral
- Department of Physics and Materials Science, Université du Luxembourg, 162A avenue de la Faïencerie, Luxembourg L-1511, Grand Duchy of Luxembourg
| | - Evelyn Pratami Sinaga
- Department of Physics and Materials Science, Université du Luxembourg, 162A avenue de la Faïencerie, Luxembourg L-1511, Grand Duchy of Luxembourg
| | - Dirk Honecker
- ISIS Neutron and Muon Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton OX11 0QX, United Kingdom
| | - Diego Alba Venero
- ISIS Neutron and Muon Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton OX11 0QX, United Kingdom
| | - Ivan Titov
- Department of Physics and Materials Science, Université du Luxembourg, 162A avenue de la Faïencerie, Luxembourg L-1511, Grand Duchy of Luxembourg
| | - Andreas Michels
- Department of Physics and Materials Science, Université du Luxembourg, 162A avenue de la Faïencerie, Luxembourg L-1511, Grand Duchy of Luxembourg
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16
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Norouzi-Inallu M, Kameli P, Ghotbi Varzaneh A, Abdolhosseini Sarsari I, Abbasi Eskandari M, Orue I, Rodríguez-Crespo B, Chernenko V. Influence of W doping on the structure, magnetism and exchange bias in Ni 47Mn 40Sn 13-xW xHeusler alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:225803. [PMID: 35134793 DOI: 10.1088/1361-648x/ac5311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
The influence of the W-doping on the martensitic transformation, magnetic properties and exchange bias (EB) effect in the Ni47Mn40Sn13-xWx(x= 0, 0.5, 1, 1.25 at.%) magnetic shape memory alloys has been investigated. It is found that the W-doping causes a simultaneous reduction of both the ferromagnetic (FM) exchange coupling and enhancement of the magnetic anisotropy, leading to a decrease of the magnetic moment of the low-temperature phase and to a higher attainable EB. The magnetic memory measurements reveal the presence of a glassy magnetic ground state, which can significantly impact the reduction of magnetization and enhancement of EB in the studied bulk alloys. It is argued that the glassy magnetic ground state originates from the partial magnetic disorder resulting from the correlation between the antiferromagnetic and FM states. The results demonstrate that the doping by W instead of Sn is an efficient tool to tailor the EB effect in the Ni-Mn-Sn-based Heusler alloys, whereby they are promising for spintronic applications.
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Affiliation(s)
- M Norouzi-Inallu
- Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - P Kameli
- Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - A Ghotbi Varzaneh
- Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | | | - M Abbasi Eskandari
- Department of Physics & RQMP, Sherbrooke University, Sherbrooke, Quebec, Canada
| | - I Orue
- SGiker, Vicerrectorado de Inv. UPV/EHU, Leioa 48940, Spain
| | - B Rodríguez-Crespo
- BCMaterials, Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, Leioa 48940, Spain
| | - V Chernenko
- BCMaterials, Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, Leioa 48940, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao 48009, Spain
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17
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Narayanaswamy V, Al-Omari IA, Kamzin AS, Issa B, Obaidat IM. Tailoring Interfacial Exchange Anisotropy in Hard-Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:262. [PMID: 35055278 PMCID: PMC8781948 DOI: 10.3390/nano12020262] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 12/30/2022]
Abstract
Magnetically hard-soft core-shell ferrite nanoparticles are synthesized using an organometallic decomposition method through seed-mediated growth. Two sets of core-shell nanoparticles (S1 and S2) with different shell (Fe3O4) thicknesses and similar core (CoFe2O4) sizes are obtained by varying the initial quantities of seed nanoparticles of size 6.0 ± 1.0 nm. The nanoparticles synthesized have average sizes of 9.5 ± 1.1 (S1) and 12.2 ± 1.7 (S2) nm with corresponding shell thicknesses of 3.5 and 6.1 nm. Magnetic properties are investigated under field-cooled and zero-field-cooled conditions at several temperatures and field cooling values. Magnetic heating efficiency for magnetic hyperthermia applications is investigated by measuring the specific absorption rate (SAR) in alternating magnetic fields at several field strengths and frequencies. The exchange bias is found to have a nonmonotonic and oscillatory relationship with temperature at all fields. SAR values of both core-shell samples are found to be considerably larger than that of the single-phase bare core particles. The effective anisotropy and SAR values are found to be larger in S2 than those in S1. However, the saturation magnetization displays the opposite behavior. These results are attributed to the occurrence of spin-glass regions at the core-shell interface of different amounts in the two samples. The novel outcome is that the interfacial exchange anisotropy of core-shell nanoparticles can be tailored to produce large effective magnetic anisotropy and thus large SAR values.
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Affiliation(s)
- Venkatesha Narayanaswamy
- Department of Medical Diagnostic Imaging, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates;
| | | | - Aleksandr S. Kamzin
- Laboratory of Ferroelectricity and Magnetism Physics, Ioffe Physical Technical Institute, 194021 St. Petersburg, Russia;
| | - Bashar Issa
- Department of Medical Diagnostic Imaging, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates;
| | - Ihab M. Obaidat
- Department of Physics, United Arab Emirates University, Al-Ain 15551, United Arab Emirates
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18
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Samanta S, Ghosh S, Mandal K. Observation of giant exchange bias effect in Ni-Mn-Ti all- d-metal Heusler alloy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:105801. [PMID: 34847541 DOI: 10.1088/1361-648x/ac3e9b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
We report a giant exchange bias (EB) field of about 3.68 kOe during field cooled process in all-d-metal Ni40(FeCo)4Mn36Ti20Heusler alloy. The study of magnetic memory effect and isothermal magnetic relaxation processes suggest that the giant EB field arises due to the possible coexistence of antiferromagnetic (AFM) and ferromagnetic (FM) phase exchange interaction in the studied system at temperatures below 35 K. Furthermore, the temperature and cooling field dependence of EB effect are analyzed which are related to the change in unidirectional anisotropy at FM/AFM interface. The study of a well-established training effect confirms the intrinsic nature of the observed EB behavior. This result will open up a new way toward the development of EB materials considering all-d-metal Heusler alloy systems.
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Affiliation(s)
- Saheli Samanta
- Magnetism Laboratory, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Sector III, Kolkata 700106, India
| | - Subrata Ghosh
- Magnetism Laboratory, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Sector III, Kolkata 700106, India
| | - Kalyan Mandal
- Magnetism Laboratory, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Sector III, Kolkata 700106, India
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19
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Chen RR, Chen G, Ren X, Ge J, Ong SJH, Xi S, Wang X, Xu ZJ. SmCo 5 with a Reconstructed Oxyhydroxide Surface for Spin-Selective Water Oxidation at Elevated Temperature. Angew Chem Int Ed Engl 2021; 60:25884-25890. [PMID: 34561927 DOI: 10.1002/anie.202109065] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Indexed: 11/06/2022]
Abstract
The efficiency of electrolytic hydrogen production is limited by the slow reaction kinetics of oxygen evolution reaction (OER). Surface-reconstructed ferromagnetic (FM) catalysts with a spin-pinning effect at the FM/oxyhydroxide interface could enhance the spin-dependent OER kinetics. However, in real-life applications, electrolyzers are operated at elevated temperature, which may disrupt the spin orientations of FM catalysts and limit their performance. In this study, we prepared surface-reconstructed SmCo5 /CoOx Hy , which possesses polarized spins at the FM/oxyhydroxide interface that lead to excellent OER activity. These interfacial polarized spins could be further aligned through a magnetization process, which further enhanced the OER performance. Moreover, the operation temperature was elevated to mimic the practical operation conditions of water electrolyzers. It was found that the OER activity enhancement of the magnetized SmCo5 /CoOx Hy catalyst could be preserved up to 60 °C.
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Affiliation(s)
- Riccardo Ruixi Chen
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.,Energy Research Institute@Nanyang Technological University, Interdisciplinary Graduate School, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Gao Chen
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Xiao Ren
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jingjie Ge
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Samuel Jun Hoong Ong
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.,Singapore-HUJ Alliance for Research and Enterprise, NEW-CREATE Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore, 138602, Singapore
| | - Shibo Xi
- Institute of Chemical and Engineering Science A*Star, 1 Pesek Road, Singapore, 627833, Singapore
| | - Xin Wang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zhichuan J Xu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.,Energy Research Institute@Nanyang Technological University, Interdisciplinary Graduate School, 50 Nanyang Avenue, Singapore, 639798, Singapore.,Singapore-HUJ Alliance for Research and Enterprise, NEW-CREATE Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore, 138602, Singapore.,Institute of Chemical and Engineering Science A*Star, 1 Pesek Road, Singapore, 627833, Singapore
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20
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Chen RR, Chen G, Ren X, Ge J, Ong SJH, Xi S, Wang X, Xu ZJ. SmCo
5
with a Reconstructed Oxyhydroxide Surface for Spin‐Selective Water Oxidation at Elevated Temperature. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Riccardo Ruixi Chen
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
- Energy Research Institute@Nanyang Technological University Interdisciplinary Graduate School 50 Nanyang Avenue Singapore 639798 Singapore
| | - Gao Chen
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Xiao Ren
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Jingjie Ge
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Samuel Jun Hoong Ong
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
- Singapore-HUJ Alliance for Research and Enterprise NEW-CREATE Phase II Campus for Research Excellence and Technological Enterprise (CREATE) 1 CREATE Way Singapore 138602 Singapore
| | - Shibo Xi
- Institute of Chemical and Engineering Science A*Star 1 Pesek Road Singapore 627833 Singapore
| | - Xin Wang
- School of Chemical and Biomedical Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Zhichuan J. Xu
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
- Energy Research Institute@Nanyang Technological University Interdisciplinary Graduate School 50 Nanyang Avenue Singapore 639798 Singapore
- Singapore-HUJ Alliance for Research and Enterprise NEW-CREATE Phase II Campus for Research Excellence and Technological Enterprise (CREATE) 1 CREATE Way Singapore 138602 Singapore
- Institute of Chemical and Engineering Science A*Star 1 Pesek Road Singapore 627833 Singapore
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21
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Routh S, Thirupathaiah S. Observation of Exchange Bias in Antiferromagnetic Cr 0.79Se Due to the Coexistence of Itinerant Weak Ferromagnetism at Low Temperatures. ACS OMEGA 2021; 6:28012-28018. [PMID: 34723001 PMCID: PMC8552323 DOI: 10.1021/acsomega.1c03986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
We report on the structural, electrical transport, and magnetic properties of antiferromagnetic transition-metal monochalcogenide Cr0.79Se. Different from the existing off-stoichiometric compositions, Cr0.79Se is found to be synthesized into the same NiAs-type hexagonal crystal structure as that of CrSe. Resistivity data suggest Cr0.79Se to be a Fermi-liquid-type metal at low temperatures, while at intermediate temperatures, the resistivity depends sublinearly on the temperature. Eventually, at elevated temperatures, the rate of change of resistivity rapidly decreases with increasing temperature. Magnetic measurements suggest a transition from the paramagnetic phase to an antiferromagnetic phase at a Néel temperature of 225 K. Further reduction of the sample temperature results in the coexistence of weak ferromagnetism along with the antiferromagnetic phase below 100 K. As a result, below 100 K, we identify a significant exchange bias due to the interaction between the ferro- and antiferromagnetic phases. In addition, from temperature-dependent X-ray diffraction measurements, we observe that the NiAs-type structure is stable up to as high as 600 °C.
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Affiliation(s)
- Sayan Routh
- Department of Condensed Matter
Physics and Material Sciences, S N Bose
National Centre for Basic Sciences, Kolkata, West Bengal 700106, India
| | - Setti Thirupathaiah
- Department of Condensed Matter
Physics and Material Sciences, S N Bose
National Centre for Basic Sciences, Kolkata, West Bengal 700106, India
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22
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Liu XC, Zhu M, Xia SQ. Room-Temperature Ferromagnetism in Mg 1-xMn 2+xAs 2 with Layered Structure. Inorg Chem 2021; 60:14357-14363. [PMID: 34450003 DOI: 10.1021/acs.inorgchem.1c02040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of Mg/Mn mixed intermetallic compounds Mg1-xMn2+xAs2 (x = 0.17, 0.48, 0.69) were synthesized by using metal flux reactions. Single-crystal X-ray diffraction measurements indicated that CaAl2Si2-type phases with Mn and Mg atoms located on the cation sites (Wickoff site: 1a) were obtained. The special structure of these Mg1-xMn2+xAs2 compounds corresponded to unique magnetic behavior, which led to increased divergence between zero-field-cooling (ZFC) and field-cooling magnetic susceptibilities with decreasing temperature. The small magnetic hysteresis loop measured at 300 K for Mg0.31(2)Mn2.69As2 revealed its room-temperature ferromagnetism, and its ZFC exchange bias behavior at low temperatures indicated the existence of both ferromagnetic (FM) and antiferromagnetic (AFM) interactions. Spin-polarized density functional theory calculations were also performed to verify the magnetic ground state, and these were consistent with the experimental results.
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Affiliation(s)
- Xiao-Cun Liu
- School of Civil Engineering, Shandong Jiaotong University, Jinan, Shandong 250023, People's Republic of China
| | - Min Zhu
- State Key Laboratory of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan, Shandong 250100, People's Republic of China.,School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, People's Republic of China
| | - Sheng-Qing Xia
- State Key Laboratory of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan, Shandong 250100, People's Republic of China
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23
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Alexandrakis V, Rodríguez-Aseguinolaza I, Anastasakos-Paraskevopoulos D, Barandiarán JM, Chernenko V, Porro JM. Spontaneous Zero-Field Cooling Exchange Bias in Ni-Co-Mn-Sn Metamagnetic Heusler Sputtered Film. NANOMATERIALS 2021; 11:nano11092188. [PMID: 34578503 PMCID: PMC8472263 DOI: 10.3390/nano11092188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 11/29/2022]
Abstract
Metamagnetic off-stoichiometric Heusler alloys are actively being investigated because of their great potential as magnetocaloric materials. These properties are intimately related to the nanoscale homogeneity of their magnetic properties, mainly due to a strong influence of the nature of the exchange interactions between Mn atoms on the magnetism of the alloys. In this work, a spontaneous exchange bias phenomenon on a Ni–Co–Mn–Sn metamagnetic Heusler sputtered film is presented and studied in detail. More particularly, a series of DC magnetization curves measured as a function of the temperature demonstrates that the system exhibits canonical spin glass-like features. After a careful study of the field-cooling and zero-field-cooling curves measured on this system, the existence of magnetic inhomogeneities is inferred, as a consequence of the competition between ferromagnetic and antiferromagnetic exchange interactions between Mn atoms. Further AC susceptibility measurements on this system demonstrate that the underlying exchange bias phenomenon can be attributed to a magnetic clusters model based on superferromagnetic-like interactions present in the film. These findings suggest that the spontaneous exchange bias exhibited by the studied system is a consequence of the formation of this superferromagnetic-like state.
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Affiliation(s)
- Vasileios Alexandrakis
- Institute of Nanoscience and Nanotechology, National Center for Scientific Research “Demokritos”, 15310 Agia Paraskevi, Greece;
- Correspondence: (V.A.); (J.M.P.)
| | - Iván Rodríguez-Aseguinolaza
- Department of Electricity & Electronics, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain; (I.R.-A.); (J.M.B.); (V.C.)
| | | | - Jose Manuel Barandiarán
- Department of Electricity & Electronics, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain; (I.R.-A.); (J.M.B.); (V.C.)
| | - Volodymyr Chernenko
- Department of Electricity & Electronics, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain; (I.R.-A.); (J.M.B.); (V.C.)
- Basque Center for Materials, Applications and Nanostructures “BCMaterials”, 48940 Leioa, Spain
- Ikerbasque—Basque Foundation for Science, 48009 Bilbao, Spain
| | - Jose Maria Porro
- Basque Center for Materials, Applications and Nanostructures “BCMaterials”, 48940 Leioa, Spain
- Ikerbasque—Basque Foundation for Science, 48009 Bilbao, Spain
- Correspondence: (V.A.); (J.M.P.)
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24
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Ma Y, Yang Y, Gao Y, Hu Y. Optimization of spontaneous exchange bias in Mn-rich Heusler alloys. Phys Chem Chem Phys 2021; 23:17365-17373. [PMID: 34350446 DOI: 10.1039/d1cp01797g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
At low temperature, spontaneous (zero-field-cooled, SEB) and traditional (field-cooled) exchange bias effects may be induced in a series of NiMn-based Heusler alloys, and the exchange bias is commonly sensitive to alloying elements and compositions, while the mechanisms especially for SEB are still elusive. Therefore, the SEB in Mn-rich Heusler alloys with coexistence of ferromagnetic and antiferromagnetic exchange interactions is numerically studied by performing a modified Monte Carlo simulation. The intrinsic magnetocrystalline anisotropies (KAF), exchange interactions (JFM-AF and JAF-AF), and occupation probabilities (xFM) are directly tuned to establish their dependencies of zero-field-cooled/field-cooled thermomagnetic curves and zero-field-cooled magnetization hysteresis loops. The results indicate that the freezing temperature is monotonically enhanced with increasing KAF and varies nonmonotonically with other parameters, and at 5 K, the irreversibility arising from antiferromagnetic components becomes high enough to trigger SEB even though no spin glass state exists. The SEB is nonmonotonic with KAF, JFM-AF, JAF-AF, and xFM, and its maximum value will be obtained at KAF = 4.5 × 106 J m-3, JFM-AF = 5 meV, JAF-AF = -5 meV, or xFM = 0.3. On the contrary, the coercivity is also nonmonotonic with KAF and JFM-AF while monotonic with JAF-AF and xFM. The values of the SEB field are nearly one order of magnitude smaller than those of coercivity, consistent with experimental data. The magnetic relaxation properties are calculated to propose two factors, i.e., ferromagnetic-like domain between ferromagnetic and antiferromagnetic components and decay rate, to determine the final SEB. This work demonstrates the mechanisms to optimize SEB in Mn-rich Heusler alloys, and physically the results obtained are also suitable for other material systems with spontaneous ferromagnet/antiferromagnet phase separations.
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Affiliation(s)
- Yitian Ma
- Department of Physics, College of Sciences, Northeastern University, Shenyang 110819, China.
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25
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Kumari K, Kumar A, Lee JE, Koo BH. Investigating the origin of exchange bias effect in ferromagnetic FeNi nanoparticles prepared via controlled synthesis. APPLIED NANOSCIENCE 2021. [DOI: 10.1007/s13204-021-01870-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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26
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Ling Y, Hu Y, Wang H, Niu B, Chen J, Liu R, Yuan Y, Wang G, Wu D, Xu M, Han Z, Du J, Xu Q. Strain Control of Phase Transition and Exchange Bias in Flexible Heusler Alloy Thin Films. ACS APPLIED MATERIALS & INTERFACES 2021; 13:24285-24294. [PMID: 33988027 DOI: 10.1021/acsami.1c03701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The practical applications for the distinctive functions of metamagnetic Heusler alloys, such as magnetic shape memory effect, various caloric effects, etc., strongly depend on the phase transition temperatures. Here, flexible Heusler alloy Ni-Mn-Sn films have been deposited on mica substrates by pulsed laser deposition with a Ti buffer layer. Clear ferromagnetic (FM) transition followed by the martensitic transformation at around room temperature and exchange bias (EB) with a blocking temperature of 70 K are observed. Under the application of both tensile and compressive strains by bending the mica substrates, all the characteristic temperatures of Ni-Mn-Sn films, including the FM transition temperature, martensitic transformation temperature, and blocking temperature of EB, are significantly increased by about 10 K. Furthermore, EB field and coercivity are both strongly strengthened, which is mainly caused by the simultaneous enhancement of FM and anti-FM Mn-Mn coupling because of their shortened separations by strain and verified by the Monte Carlo simulation results. The strain controlling for structural and magnetic properties provides efficient manipulation for Heusler alloy-based magnetic devices.
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Affiliation(s)
- Yechao Ling
- School of Physics, Southeast University, Nanjing 211189, China
| | - Yong Hu
- Department of Physics, College of Sciences, Northeastern University, Shenyang 110819, China
| | - Haobo Wang
- Department of Physics, Changshu Institute of Technology, Changshu 215500, China
| | - Ben Niu
- National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Jiangsu Key Laboratory for Artificial Functional Materials, Nanjing University, Nanjing 210093, China
| | - Jiawei Chen
- School of Physics, Southeast University, Nanjing 211189, China
| | - Ruobai Liu
- Department of Physics, Nanjing University, Nanjing 210093, China
| | - Yuan Yuan
- Department of Physics, Nanjing University, Nanjing 210093, China
| | - Guangyu Wang
- School of Physics, Southeast University, Nanjing 211189, China
| | - Di Wu
- National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Jiangsu Key Laboratory for Artificial Functional Materials, Nanjing University, Nanjing 210093, China
- National Laboratory of Solid State Microstructures, Nanjing 210008, China
| | - Mingxiang Xu
- School of Physics, Southeast University, Nanjing 211189, China
| | - Zhida Han
- Department of Physics, Changshu Institute of Technology, Changshu 215500, China
| | - Jun Du
- Department of Physics, Nanjing University, Nanjing 210093, China
- National Laboratory of Solid State Microstructures, Nanjing 210008, China
| | - Qingyu Xu
- School of Physics, Southeast University, Nanjing 211189, China
- National Laboratory of Solid State Microstructures, Nanjing 210008, China
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27
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Deltell A, Mohamed AEMA, Álvarez-Alonso P, Ipatov M, Andrés J, González J, Sánchez T, Zhukov A, Escoda M, Suñol J, López Antón R. Martensitic transformation, magnetic and magnetocaloric properties of Ni–Mn–Fe–Sn Heusler ribbons. JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY 2021; 12:1091-1103. [DOI: 10.1016/j.jmrt.2021.03.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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28
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Tian F, Li Y, Zhao Q, Cao K, Wang D, Dai Z, Yu Z, Ke X, Zhang Y, Zhou C, Zuo W, Yang S, Song X. Giant exchange bias induced via tuning interfacial spins in polycrystalline Fe 3O 4/CoO bilayers. Phys Chem Chem Phys 2021; 23:4805-4810. [PMID: 33605273 DOI: 10.1039/d0cp05902a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A giant exchange bias (EB) of 9600 Oe was observed in polycrystalline Fe3O4/CoO layers at 10 K after 20 kOe field cooling, and was attributed to the strong exchange coupling formed by the interfacial spins between the polycrystalline Fe3O4 and the CoO layer. It was found that at 10 K, the magnetic-moment difference (ΔM) between the zero field cooling curves and field cooling curves first increases and then decreases with the change of the field, and it reaches the maximum value at a field of 20 kOe, which suggests that the interfacial spins can be tuned by the cooling field. Furthermore, other magnetic properties, including field dependence, temperature dependence, and training effects, were investigated, which further confirmed that the interfacial spins play an important role in the EB effect. This work provides a method to tune the magnitude of the EB effect and reveals the mechanism of the dependency of EB on interfacial spins, which could guide the design of giant-EB-effect materials.
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Affiliation(s)
- Fanghua Tian
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Yebei Li
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Qizhong Zhao
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Kaiyan Cao
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Dingchen Wang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Zhiyong Dai
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Zhonghai Yu
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Xiaoqin Ke
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Yin Zhang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Chao Zhou
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Wenliang Zuo
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Sen Yang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Xiaoping Song
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
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29
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Silva AG, Salcedo Rodríguez KL, Contreras Medrano CP, Lourenço GSG, Boldrin M, Baggio-Saitovitch E, Bufaiçal L. Griffiths phase and spontaneous exchange bias in La 1.5Sr 0.5CoMn 0.5Fe 0.5O 6. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:065804. [PMID: 33113517 DOI: 10.1088/1361-648x/abc595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
La1.5Sr0.5CoMn0.5Fe0.5O6 (LSCMFO) compound was prepared by solid state reaction and its structural, electronic and magnetic properties were investigated. The material forms in rhombohedral [Formula: see text] structure, and the presence of distinct magnetic interactions leads to the formation of a Griffiths phase above its FM transition temperature (150 K), possibly related to the nucleation of small short-ranged ferromagnetic clusters. At low temperatures, a spin glass-like phase emerges and the system exhibits both the conventional and the spontaneous exchange bias (EB) effects. These results resemble those reported for La1.5Sr0.5CoMnO6 but are discrepant to those found when Fe partially substitutes Co in La1.5Sr0.5(Co1-x Fe x )MnO6, for which the EB effect is observed in a much broader temperature range. The unidirectional anisotropy observed for LSCMFO is discussed and compared with those of resembling double-perovskite compounds, being plausibly explained in terms of its structural and electronic properties.
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Affiliation(s)
- A G Silva
- Instituto de Física, Universidade Federal de Goiás, 74001-970, Goiânia, GO, Brazil
| | - K L Salcedo Rodríguez
- Instituto de Física La Plata, Facultad de Ciencias Exactas, UNLP, CONICET, 1900, La Plata, Argentina
- Centro Brasileiro de Pesquisas Físicas, 22290-180, Rio de Janeiro, RJ, Brazil
| | | | - G S G Lourenço
- Instituto de Física, Universidade Federal de Goiás, 74001-970, Goiânia, GO, Brazil
| | - M Boldrin
- Instituto de Física, Universidade Federal de Goiás, 74001-970, Goiânia, GO, Brazil
| | - E Baggio-Saitovitch
- Centro Brasileiro de Pesquisas Físicas, 22290-180, Rio de Janeiro, RJ, Brazil
| | - L Bufaiçal
- Instituto de Física, Universidade Federal de Goiás, 74001-970, Goiânia, GO, Brazil
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30
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Zhang L, Zhang J, Li K, Zhou C, Yao Y, Tan TT, Wang D, Yang S, Li S, Carpenter MA. Glassy Magnetic Transitions and Accurate Estimation of Magnetocaloric Effect in Ni-Mn Heusler Alloys. ACS APPLIED MATERIALS & INTERFACES 2020; 12:43646-43652. [PMID: 32876430 DOI: 10.1021/acsami.0c11308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, the structural and magnetic transitions of Heusler alloy Ni50Mn34In14Ga2 have been carefully studied through measurements of heat flow and magnetization under DC and AC magnetic fields. This alloy undergoes the transition sequence of spin-glassy martensite (SPM) → ferromagnetic austenite (FA) → paramagnetic austenite at ∼225 and ∼305 K, respectively, during heating. Splitting of zero-field-cooling (ZFC)/field-cooling (FC) curves in martensite is caused by the slowdown dynamics of spin glass as evidenced by frequency dispersion and aging effects. The development of a spin-glass state is believed to be the result of strain relaxation and interaction of ferroelastic twin walls in the martensite. The magnetocaloric effect (MCE) at the SPM-FA transition was then measured using indirect, quasi-direct, and direct methods. The MCE magnitudes are controlled by the entropy changes associated with the first-order martensite transition and magnetic ordering of austenite under the magnetic field. The existence of a spin-glass state in martensite can also improve the reversibility of the magnetostructural transitions, which is beneficial for the improvement of the reversibility of associated MCE. These results provide an in-depth understanding of the transitions and magnetic properties of the Ni-Mn Heusler alloys and suggest that the MCE at the first-order magnetostructural transitions estimated solely using indirect methods may need some revision.
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Affiliation(s)
- Le Zhang
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Ji Zhang
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Kaili Li
- School of Science and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chao Zhou
- School of Science and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yin Yao
- Electron Microscope Unit, Mark Wainwright Analytical Centre, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Thiam Teck Tan
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Danyang Wang
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Sen Yang
- School of Science and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an 710049, China
| | - Sean Li
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Michael A Carpenter
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
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31
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Nevgi R, Priolkar KR, Righi L, Solzi M, Cugini F, Dias ET, Nigam AK. Lattice strain accommodation and absence of pre-transition phases in Ni 50Mn 25+xIn 25-x. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:505801. [PMID: 32985415 DOI: 10.1088/1361-648x/abb17f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 08/21/2020] [Indexed: 06/11/2023]
Abstract
The stoichiometric Ni50Mn25In25Heusler alloy transforms from a stable ferromagnetic austenitic ground state to an incommensurate modulated martensitic ground state with a progressive replacement of In with Mn without any pre-transition phases. The absence of pre-transition phases like strain glass in Ni50Mn25+xIn25-xalloys is explained to be the ability of the ferromagnetic cubic structure to accommodate the lattice strain caused by atomic size differences of In and Mn atoms. Beyond the critical value ofx= 8.75, the alloys undergo martensitic transformation despite the formation of ferromagnetic and antiferromagnetic clusters and the appearance of a super spin glass state.
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Affiliation(s)
- R Nevgi
- Department of Physics, Goa University, Taleigao Plateau, Goa 403206, India
| | - K R Priolkar
- Department of Physics, Goa University, Taleigao Plateau, Goa 403206, India
| | - L Righi
- Department of Chemistry, Parma University, Parco Area delle Scienze 17/a 43124 Parma, Italy
| | - M Solzi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A 43124 Parma, Italy
| | - F Cugini
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A 43124 Parma, Italy
| | - E T Dias
- Department of Condensed Matter Physics and Material Science, Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
| | - A K Nigam
- Department of Condensed Matter Physics and Material Science, Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
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32
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The Phase Relations of the Co-Ni-In Ternary System at 673 K and 873 K and Magnetic Properties of Their Compounds. MATERIALS 2020; 13:ma13183990. [PMID: 32916900 PMCID: PMC7558481 DOI: 10.3390/ma13183990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 11/17/2022]
Abstract
The phase relationships of the ternary Co-Ni-In system at 673 K and 873 K were investigated by means of powder X-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy, and optical microscopy. Though CoIn2 does not exist at 873 K, the ternary solid solution Co1-xNixIn2 exists at both 673 K and 873 K with different composition ranges. The Rietveld refinements were carried out to investigate the crystal structure of Co1-xNixIn2 (x = 0.540, and 0.580) and Ni2-xCoxIn3 (x = 0.200). The magnetization dependence of temperature (MT) curves of Ni2-xCoxIn3 (x = 0.200) and Co1-xNixIn2 (x = 0.540) are similar to those of the ferromagnetic shape memory alloys Ni-Mn-A (A = Ga, Sn, and In), but do not undergo martensitic transformation. The maximum magnetic entropy changes in Ni2-xCoxIn3 (x = 0.200) and Co1-xNixIn2 (x = 0.540) under 3T are 1.25 and 1.475 J kg-1K-1, respectively.
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33
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Zheng G, Xie WQ, Albarakati S, Algarni M, Tan C, Wang Y, Peng J, Partridge J, Farrar L, Yi J, Xiong Y, Tian M, Zhao YJ, Wang L. Gate-Tuned Interlayer Coupling in van der Waals Ferromagnet Fe_{3}GeTe_{2} Nanoflakes. PHYSICAL REVIEW LETTERS 2020; 125:047202. [PMID: 32794802 DOI: 10.1103/physrevlett.125.047202] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/19/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
The weak interlayer coupling in van der Waals (vdW) magnets has confined their application to two dimensional (2D) spintronic devices. Here, we demonstrate that the interlayer coupling in a vdW magnet Fe_{3}GeTe_{2} (FGT) can be largely modulated by a protonic gate. With the increase of the protons intercalated among vdW layers, interlayer magnetic coupling increases. Because of the existence of antiferromagnetic layers in FGT nanoflakes, the increasing interlayer magnetic coupling induces exchange bias in protonated FGT nanoflakes. Most strikingly, a rarely seen zero-field cooled (ZFC) exchange bias with very large values (maximally up to 1.2 kOe) has been observed when higher positive voltages (V_{g}≥4.36 V) are applied to the protonic gate, which clearly demonstrates that a strong interlayer coupling is realized by proton intercalation. Such strong interlayer coupling will enable a wider range of applications for vdW magnets.
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Affiliation(s)
- Guolin Zheng
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - Wen-Qiang Xie
- Department of Physics, South China University of Technology, Guangzhou 510640, China
| | | | - Meri Algarni
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - Cheng Tan
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - Yihao Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei 230031, Anhui, China
| | - Jingyang Peng
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - James Partridge
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - Lawrence Farrar
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - Jiabao Yi
- Global Innovative Center for Advanced Nanomaterials, School of Engineering, University of Newcastle, Callaghan NSW 2308, Australia
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei 230031, Anhui, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei 230031, Anhui, China
- Department of Physics, School of Physics and Materials Science, Anhui University, Hefei 230601, Anhui, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yu-Jun Zhao
- Department of Physics, South China University of Technology, Guangzhou 510640, China
| | - Lan Wang
- School of Science, RMIT University, Melbourne VIC 3001, Australia
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34
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Zhang L, Lou X, Zhou C, Yang S, Ren X, Wang D, Carpenter MA. Coupling between phase transitions and glassy magnetic behaviour in Heusler alloy Ni 50Mn 34In 8Ga 8. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:325402. [PMID: 32162615 DOI: 10.1088/1361-648x/ab7f04] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
The transition sequence in the Heusler alloy Ni50Mn34In8Ga8has been determined from measurements of elasticity, heat flow and magnetism to be paramagnetic austenite → paramagnetic martensite → ferromagnetic martensite at ∼335 and ∼260 K, respectively, during cooling. The overall pattern of elastic stiffening/softening and acoustic loss is typical of a system with bilinear coupling between symmetry breaking strain and the driving structural/electronic order parameter, and a temperature interval below the transition point in which ferroelastic twin walls remain mobile under the influence of external stress. Divergence between zero-field-cooling and field-cooling determinations of DC magnetisation below ∼220 K indicates that a frustrated magnetic glass develops in the ferromagnetic martensite. An AC magnetic anomaly which shows Vogel-Fulcher dynamics in the vicinity of ∼160 K is evidence of a further glassy freezing process. This coincides with an acoustic loss peak and slight elastic stiffening that is typical of the outcome of freezing of ferroelastic twin walls. The results suggest that local strain variations associated with the ferroelastic twin walls couple with local moments to induce glassy magnetic behaviour.
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Affiliation(s)
- Le Zhang
- Frontier Institute of Science and Technology and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom
- School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Xiaojie Lou
- Frontier Institute of Science and Technology and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China
| | - Chao Zhou
- School of Science, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Sen Yang
- School of Science, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Xiaobing Ren
- Frontier Institute of Science and Technology and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China
- Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki, Japan
| | - Danyang Wang
- School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Michael A Carpenter
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom
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Pal A, Singh P, Gangwar VK, Joshi AG, Khuntia P, Dwivedi GD, Gupta PK, Alam M, Anand K, Sethupathi K, Ghosh AK, Chatterjee S. Probing the Griffiths like phase, unconventional dual glassy states, giant exchange bias effects and its correlation with its electronic structure in Pr 2-x Sr x CoMnO 6. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:215801. [PMID: 31671415 DOI: 10.1088/1361-648x/ab5326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Crystal, electronic structure, dc and ac magnetization properties of the hole substituted (Sr2+) and partially B-site disordered double perovskite Pr2-x Sr x CoMnO6 system have been investigated. The XRD pattern analysis showed a systematic decrease in the lattice parameters owing to the enhanced oxidation states of the Co/Mn ions. The electronic structure study by XPS measurements suggested the presence of mixed valence states of the B-site ions (Co2+ /Co3+ and Mn3+ /Mn4+) with significant enhancement of the average oxidation states due to hole doping. The mere absence of electronic states near the Fermi level in the valence band (VB) spectra for both pure (x = 0.0) and Sr doped (x = 0.5) systems indicated the insulating nature of the samples. Sr substitution is observed to increase the spectral weight near the Fermi level suggesting for an enhanced conductivity of the hole doped system. The dc magnetization data divulged a Griffiths like phase above the long-range ordering temperature. A typical re-entrant spin glass like phase driven by the inherent anti-site disorder (ASD) has been recognized by ac susceptibility study for both the pure and doped systems. Most interestingly, the emergence of a new cluster glass like phase (immediately below the magnetic ordering temperature and above the spin-glass transition temperature) solely driven by the Sr substitution has been unravelled by ac magnetization dynamics study. Observation of these dual glassy states in a single system is scarce and hence placed the present system amongst the rare materials. The isothermal magnetization measurements further probed the exhibition of the giant exchange bias effect originated from the interfacial exchange interactions due to existence of low temperature antiferromagnetic clusters embedded in the glassy matrix.
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Affiliation(s)
- Arkadeb Pal
- Department of physics, Indian Institute of Technology (BHU) Varanasi, India. Department of physics, Indian Institute of Technology, Madras, India
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Yu L, Li R, Hu Y. Temperature controlled switchable exchange bias and coercivity in spin glass/ferromagnet multilayers under tilting magnetizing. Phys Chem Chem Phys 2020; 22:9749-9758. [PMID: 32330219 DOI: 10.1039/d0cp00605j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A modified Monte Carlo method is used to study the temperature dependence of exchange bias and coercivity behaviors in ferromagnetic layers sandwiched by spin glass layers based on three stacking structures. An interesting phenomenon of 100% temperature controlled switch between the exchange bias field and coercivity is observed. Angular dependence of exchange bias field and coercivity behaviors indicate that there exists a minimum nonzero angle between the magnetic field and ferromagnet/spin glass easy axis, depending on the stacking structure, to achieve a complete switch. We further study the thermal remnant magnetization, the Zeeman and exchange energy behaviors during hysteretic measurements and the magnetic training effect at different temperatures, designating that the spin glassy dynamics is crucial for such a smooth and full switch. This finding shows potential in designing an applicable thermally assisted read/write switchable spintronic devices, achieved simply by rotational magnetizing and nanostructure engineering.
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Affiliation(s)
- Le Yu
- Department of Physics, College of Sciences, Northeastern University, Shenyang 110819, China.
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Pandey GC, Nemkovski K, Su Y, Rath C. Evidence of anomalous conventional and spontaneous exchange bias, high coercivity in Fe doped NiCr 2O 4 spinel. Dalton Trans 2020; 49:4502-4517. [PMID: 32193522 DOI: 10.1039/d0dt00124d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NiCr2-xFexO4 (x = 0 and 0.2) polycrystalline ceramics have been synthesized successfully through a simple co-precipitation technique to study the evolution of structural and magnetic properties by doping Fe. X-ray diffraction (XRD) reveals that the high-temperature cubic phase (space group Fd3[combining macron]m) observed at 320 K in bulk NiCr2O4 is stabilized at room temperature by decreasing the particle size to nanometer in x = 0 as well as after incorporating 20 at% Fe in the NiCr2O4 lattice. The cation distribution obtained from X-ray absorption fine structure (XAFS) analysis illustrates that while in x = 0, Ni2+ and Cr3+ ions occupy the tetrahedral (A) and octahedral (B) sites, respectively, x = 0.2, Fe3+ and Cr3+ ions occupy the A and B sites, respectively, and Ni2+ ions are distributed among the A and B sites. This transformation from the normal to mixed spinel structure strongly affects the magnetic properties. While the paramagnetic to long-range ferrimagnetic ordering temperature TC is enhanced from 71 to 192 K, significantly large coercive field (HC) of ∼29 kOe is observed for x = 0.2 as compared to the HC ∼13 kOe for x = 0. Moreover, unusually large conventional and spontaneous exchange bias fields of ∼26 and ∼2.6 kOe are observed for x = 0.2, which is absent for x = 0. The presence of anomalous exchange bias field is ascribed to the unidirectional exchange anisotropy between the two magnetic sublattices at A and B sites. The training effect of the exchange bias field is discussed using a phenomenological model, which considers the contribution from irreversible uncompensated spins that modify the exchange anisotropy at the interface between A and B magnetic sublattices. In addition, diffuse neutron scattering (DNS) with XYZ analysis is employed for both compositions to clearly illustrate the low-temperature peculiar magnetic phase transitions such as spin spiral transition, TS and spin lock-in transition, Tl. The DNS demonstrates that while Tl decreases from 10 K to 7 K with the incorporation of Fe in the NiCr2O4 lattice, TS significantly increases from 28 K to 50 K.
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Affiliation(s)
- G C Pandey
- School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi, 221005, India.
| | - K Nemkovski
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstr. 1, 85748 Garching, Germany
| | - Y Su
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstr. 1, 85748 Garching, Germany
| | - Chandana Rath
- School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi, 221005, India.
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Sarkar SK, Ahlawat S, Kaushik SD, Babu PD, Sen D, Honecker D, Biswas A. Magnetic ordering of the martensite phase in Ni-Co-Mn-Sn-based ferromagnetic shape memory alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:115801. [PMID: 31739303 DOI: 10.1088/1361-648x/ab5876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The magnetic state of low temperature martensite phase in Co-substituted Ni-Mn-Sn-based ferromagnetic shape memory alloys (FSMAs) has been investigated, in view of numerous conflicting reports of occurrences of spin glass (SG), superparamagnetism (SPM) or long range anti-ferromagnetic (AF) ordering. Combination of DC magnetization, AC susceptibility and small angle neutron scattering (SANS) studies provide clear evidence for AF order in the martensitic phase of Ni45Co5Mn38Sn12 alloy and rule out SPM and SG orders. Identical studies on another alloy of close composition, Ni44Co6Mn40Sn10, point to the presence of SG order in the martensitic phase and the absence of SPM behavior, contrary to earlier reports. SANS results do show the presence of nanometre-sized clusters but they are found to grow in size from 3 nm at 30 K to 11 nm at 300 K, and do not correlate with magnetism in these alloys.
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Affiliation(s)
- Sudip Kumar Sarkar
- Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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Exchange biased anomalous Hall effect driven by frustration in a magnetic kagome lattice. Nat Commun 2020; 11:560. [PMID: 31992704 PMCID: PMC6987238 DOI: 10.1038/s41467-020-14326-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/17/2019] [Indexed: 11/08/2022] Open
Abstract
Co[Formula: see text]Sn[Formula: see text]S[Formula: see text] is a ferromagnetic Weyl semimetal that has been the subject of intense scientific interest due to its large anomalous Hall effect. We show that the coupling of this material's topological properties to its magnetic texture leads to a strongly exchange biased anomalous Hall effect. We argue that this is likely caused by the coexistence of ferromagnetism and geometric frustration intrinsic to the kagome network of magnetic ions, giving rise to spin-glass behavior and an exchange bias.
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Kim YJ, Konishi S, Hayasaka Y, Kakeya I, Tanaka K. Magnetic and electrical properties of LuFe2O4 epitaxial thin films with a self-assembled interface structure. CrystEngComm 2020. [DOI: 10.1039/c9ce01666j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thin film of LuFe2O4, one of multiferroics, deposited on an yttria-stabilized zirconia substrate shows a unique interface structure, leading to an exchange bias effect. The thin film itself undergoes spin glass or cluster glass transition.
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Affiliation(s)
- You Jin Kim
- Department of Material Chemistry
- Graduate School of Engineering
- Kyoto University
- Kyoto 615-8510
- Japan
| | - Shinya Konishi
- Department of Material Chemistry
- Graduate School of Engineering
- Kyoto University
- Kyoto 615-8510
- Japan
| | | | - Itsuhiro Kakeya
- Department of Electronic Science and Engineering
- Graduated School of Engineering
- Kyoto University
- Kyoto 615-8510
- Japan
| | - Katsuhisa Tanaka
- Department of Material Chemistry
- Graduate School of Engineering
- Kyoto University
- Kyoto 615-8510
- Japan
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Samatham SS, Patel AK, Lukoyanov AV, Baglasov ED, Suresh KG. Magnetism of 3d and 4d doped Mn 0.7T 0.3NiGe (T = Fe, Co, Ru and Rh): bulk magnetization and ab initio calculations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:495804. [PMID: 31437830 DOI: 10.1088/1361-648x/ab3ddd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We compare the magnetic properties of 3d (Fe and Co) and 4d (Ru and Rh) transition metals doped MnNiGe using the combined results of magnetization and ab initio calculations. The alloys crystallize in austenite Ni2In-type hexagonal phase (space group: P63/mmc) with insignificant difference in the lattice parameters. Mn0.7Fe0.3NiGe and Mn0.7Co0.3NiGe exhibit spin-glass behavior, resulting from the competing ferro- and antiferromagnetic interactions. These alloys exhibit spontaneous exchange bias field of about [Formula: see text] Oe and 323 Oe, respectively. From the 4d-metal doped alloys, Mn0.7Ru0.3NiGe shows glassy behavior while long-range ferromagnetic order is confirmed in Mn0.7Rh0.3NiGe. In Mn0.7Rh0.3NiGe, in agreement with experiment and the theoretical calculations, the ground state is confirmed to be ferromagnetic because of the FM exchange interactions of the Mn magnetic moments. But in Mn1-x (Fe,Co,Ru) x NiGe alloys the calculations revealed the competing and comparable FM and AFM exchange interaction parameters, resulting in the formation of spin-glassy characteristics.
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Affiliation(s)
- S Shanmukharao Samatham
- Department of Physics, Maharaj Vijayaram Gajapathi Raj College of Engineering, Vijayaram Nagar Campus, Chintalavalasa, Vizianagaram 535005, Andhra Pradesh, India
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42
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Exotic magnetic behaviour and evidence of cluster glass and Griffiths like phase in Heusler alloys Fe 2-xMn xCrAl (0 ≤ x ≤ 1). Sci Rep 2019; 9:15888. [PMID: 31685883 PMCID: PMC6828798 DOI: 10.1038/s41598-019-52452-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/17/2019] [Indexed: 11/18/2022] Open
Abstract
We present a detailed study of structural, magnetic and thermodynamic properties of a series of Heusler alloys Fe2-xMnxCrAl (x = 0, 0.25, 0.5, 0.75 and 1). Structural investigation of this series is carried out using high resolution synchrotron X-ray diffraction. Results suggest that with increasing Mn concentration, the L21 structure of Fe2CrAl is destabilized. The DC magnetization results show a decrement in paramagnetic (PM) to ferromagnetic (FM) phase transition temperature (TC) with increasing Mn concentration. From the systematic analysis of magnetic memory effect, heat capacity, time dependent magnetization, and DC field dependent AC susceptibility studies it is observed that, Fe2CrAl exhibits cluster glass(CG)-like transition approximately at 3.9 K (Tf2). The alloys, Fe1.75Mn0.25CrAl and Fe1.5Mn0.5CrAl exhibit double CG-like transitions near Tf1 ~ 22 K, Tf2 ~ 4.2 K and Tf1 ~ 30.4 K, Tf2 ~ 9.5 K respectively, however, in Fe1.25Mn0.75CrAl, a single CG-like transition is noted at Tf2 ~ 11.5 K below TC. Interestingly, FeMnCrAl shows the absence of long ranged magnetic ordering and this alloy undergoes three CG-like transitions at ~22 K (Tf*), 16.6 K (Tf1) and 11 K (Tf2). At high temperatures, a detailed analysis of temperature response of inverse DC susceptibility clearly reveals the observation of Griffiths phase (GP) above 300 K (T*) in Fe2CrAl and this phase persists with Mn concentration with a decrement in T*.
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Zhang J, Zhou G, Yan Z, Ji H, Li X, Quan Z, Bai Y, Xu X. Interfacial Ferromagnetic Coupling and Positive Spontaneous Exchange Bias in SrFeO 3-x/La 0.7Sr 0.3MnO 3 Bilayers. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26460-26466. [PMID: 31267730 DOI: 10.1021/acsami.9b07639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Negative exchange bias is usually discovered in ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures after a field-cooling (FC) process. Relatively, positive exchange bias (PEB) is a rarely observed phenomenon. So far, almost all of the models for PEB whether undergoing FC or zero-field-cooling (ZFC) treatment have been explained by an interaction of strong AFM coupling at the interface. In this work, by selecting a special material of SrFeO3-x as the AFM layer, coupled with FM-La0.7Sr0.3MnO3 (LSMO), we obtain a novel PEB effect of the bilayer after ZFC measurement, of which the shift directions are unfixable and dependent on the initial magnetization direction. Based on a transient magnetic field to control the remanence (Mr) direction of LSMO at room temperature and then cooling below the TN of SrFeO3-x without any magnetic field disturbance, the shift direction can be locked only toward the transient magnetic field. Combined with experimental results and first-principles calculations, we propose that the above phenomena are explained as the field-induced AFM phase of SrFeO3-x transforming into the FM phase at an FM coupling bilayer interface. Thus, our finding may provide a new approach to realize and tune the zero-field-cooling PEB with FM coupling heterostructures.
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Affiliation(s)
- Jun Zhang
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
- Department of Chemistry & Chemical Engineering , Lvliang University , Lishi 033001 , China
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology , Linfen 041004 , China
| | - Guowei Zhou
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology , Linfen 041004 , China
| | - Zhi Yan
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
| | - Huihui Ji
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
| | - Xiaoli Li
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology , Linfen 041004 , China
| | - Zhiyong Quan
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology , Linfen 041004 , China
| | - Yuhao Bai
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology , Linfen 041004 , China
| | - Xiaohong Xu
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education , Linfen 041004 , China
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology , Linfen 041004 , China
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Kharkwal KC, Chaurasia R, Pramanik AK. Unusual exchange bias in Sr 2FeIrO 6/La 0.67Sr 0.33MnO 3 multilayer. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:13LT02. [PMID: 30658343 DOI: 10.1088/1361-648x/ab000a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Here, we study interface induced magnetic properties in a 3d-5d based multilayer made of La0.67Sr0.33MnO3 and double perovskite Sr2FeIrO6, respectively. Bulk La0.67Sr0.33MnO3 is metallic and shows ferromagnetic (FM) ordering above room temperature. In contrast, bulk Sr2FeIrO6, is an antiferromagnet (AFM) with a Néel temperature around 45 K ([Formula: see text]) and exhibits an insulating behavior. Two set of multilayers have been grown on SrTiO3 (1 0 0) crystal with varying thickness of FM layer. A multilayer with equal thickness of La0.67Sr0.33MnO3 and Sr2FeIrO6 (∼10 nm) shows exchange bias (EB) effect both in conventionally field cooled (FC) as well as in zero field cooled (ZFC) magnetic hysteresis measurements which is rather unusual. The ZFC EB effect is weakened both with increasing maximum field during initial magnetization process at low temperature and with increasing temperature. Interestingly, a multilayer with reduced thickness of La0.67Sr0.33MnO3 (∼5 nm) does not exhibit ZFC EB phenomenon, however, the FC EB effect is strengthened showing much higher value. We believe that an AFM type exchange coupling at the interface and its evolution during initial application of magnetic field causes this unusual EB in present multilayers.
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Affiliation(s)
- K C Kharkwal
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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Zuo S, Liu Y, Zhang Y, Xiong J, Liu J, Qiao K, Liang F, Zhao T, Hu F, Sun J, Shen B. In situ TEM study on diversified martensitic transition behaviour in Ni 50Mn 35In 15 alloys. NANOSCALE 2019; 11:4999-5004. [PMID: 30839014 DOI: 10.1039/c8nr10209k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ni-Mn-In magnetic shape-memory alloys are attractive materials due to their important functional properties relating to the martensitic transition. Understanding the complex martensitic magnetism and the transition process is of crucial importance not only from a fundamental but also from a technological point of view. Here, we demonstrate the dynamic magnetic domains and microstructures during the martensitic transition in the bulk and melt-spun ribbons of Ni50Mn35In15via in situ Lorentz transmission electron microscopy. The significant evolutionary differences in correlation with the temperature dependence of magnetization are identified between the bulk and ribbons. For a bulk alloy with L21 crystal structure at room temperature, the complete martensite with 7 M modulation in the paramagnetic state and the successive stripe magnetic domains in ferromagnetic martensite develop with a further decrease in the temperature. The stripe domains evolve into biskyrmion-like spin configurations when a perpendicular magnetic field is applied. In contrast, the partial austenitic phase always coexists with the martensitic phase in the ribbons even far below the martensitic transition temperatures and the martensitic phase presents a dominant twinning stack morphology with 5 M modulation and various magnetic domains. During the subsequent reheating-cooling cycles, the thermal hysteresis behavior and the transition reversibility in the bulk and ribbons are represented via the microstructural evolution.
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Affiliation(s)
- Shulan Zuo
- State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China.
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Sun Y, Hu P, Shi K, Wu H, Deng S, Huang Q, Mao Z, Song P, Wang L, Hao W, Deng S, Wang C. Giant zero-field cooling exchange-bias-like behavior in antiperovskite Mn 3Co 0.61Mn 0.39N compound. PHYSICAL REVIEW MATERIALS 2019; 3:10.1103/PhysRevMaterials.3.024409. [PMID: 38855475 PMCID: PMC11160320 DOI: 10.1103/physrevmaterials.3.024409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Giant zero-field cooling exchange-bias-like behavior with H EB = 3.49kOe was found in an antiperovskite Mn3Co0.61Mn0.39N compound. The magnetic structure of Mn3Co0.61Mn0.39N was resolved to be ferrimagentic ordering composed of canted Γ5g antiferromagnetic (AFM) and ferromagnetic (FM) along the [111] direction by the neutron diffraction technique. The exchange coupling model was proposed together with the first principles calculation for further understanding this exchange-bias-like behavior. It was found that the ferromagnetic exchange interaction between FM and the canted Γ5g AFM play an important role in the particular exchange-bias-like behavior. The exchange coupling constructed in the lattice is distinct from the interactions between collinear AFM and FM in conventional exchange bias system. In addition to the enhanced horizontal shift, hysteresis loops obtained after FC cooling also exhibited vertical shift. The macroscopic vertical shift of the magnetization is ascribed to the increase of the magnetic moment of canted Γ5g spins along the external magnetic field. This finding will promote the development of advanced magnetic devices.
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Affiliation(s)
- Ying Sun
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Pengwei Hu
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Kewen Shi
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Hui Wu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899–6102, United States
| | - Sihao Deng
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Qingzhen Huang
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899–6102, United States
| | - Zhiyong Mao
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Ping Song
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Lei Wang
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Weichang Hao
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Shenghua Deng
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
| | - Cong Wang
- Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191, People’s Republic of China
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Pradhan SK, Dalal B, De SK. Exchange bias effect in a finite site disordered canted antiferromagnet. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:365801. [PMID: 30074485 DOI: 10.1088/1361-648x/aad7d6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report the temperature and magnetic field dependent magnetic properties of the single-phase polycrystalline La0.8Sr0.2Cr0.7Ru0.3O3 sample to explore the intrinsic magnetic phases of the sample. Our combined temperature and field dependent magnetization studies reveal the formation of ferromagnetic (FM) cluster-glass in the antiferromagnetic (AFM) matrix of host LaCrO3. Interestingly, the as-studied sample exhibits both zero-field-cooled (horizontal shift) and field-cooled (vertical shift) exchange bias effects and, in both cases, magnitude of exchange bias field continuously increases with the decrease of temperature. Our successive hysteresis loop measurements completely ruled out the effect of any minor hysteresis loop and thus, establishes this vertical shift as conventional field-cooled exchange bias (CEB) effect, originating from the uncompensated spins of randomly substituted canted AFM spin structure. A significantly larger value of CEB field (7.5 kOe) at 5 K is achieved for a cooling field of 50 kOe, not usually observed in conventional FM/AFM interfacial exchange-bias systems.
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The Effect of Different Atomic Substitution at Mn Site on Magnetocaloric Effect in Ni50Mn35Co2Sn13 Alloy. CRYSTALS 2018. [DOI: 10.3390/cryst8080329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effect of different atomic substitutions at Mn sites on the magnetic and magnetocaloric properties in Ni50Mn35Co2Sn13 alloy has been studied in detail. The substitution of Ni or Co for Mn atoms might lower the Mn content at Sn sites, which would reduce the d-d hybridization between Ni 3d eg states and the 3d states of excess Mn atoms at Sn sites, thus leading to the decrease of martensitic transformation temperature TM in Ni51Mn34Co2Sn13 and Ni50Mn34Co3Sn13 alloys. On the other hand, the substitution of Sn for Mn atoms in Ni50Mn34Co2Sn14 would enhance the p-d covalent hybridization between the main group element (Sn) and the transition metal element (Mn or Ni) due to the increase of Sn content, thus also reducing the TM by stabilizing the parent phase. Due to the reduction of TM, a magnetostructural martensitic transition from FM austenite to weak-magnetic martensite is realized in Ni51Mn34Co2Sn13 and Ni50Mn34Co2Sn14, resulting in a large magnetocaloric effect around room temperature. For a low field change of 3 T, the maximum ∆SM reaches as high as 30.9 J/kg K for Ni50Mn34Co2Sn14. A linear dependence of ΔSM upon μ0H has been found in Ni50Mn34Co2Sn14, and the origin of this linear relationship has been discussed by numerical analysis of Maxwell’s relation.
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Koteswararao B, Chakrabarty T, Basu T, Hazra BK, Srinivasarao PV, Paulose PL, Srinath S. Large spontaneous exchange bias in a weak ferromagnet Pb 6Ni 9(TeO 6) 5. Sci Rep 2017; 7:8300. [PMID: 28811608 PMCID: PMC5557810 DOI: 10.1038/s41598-017-09056-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/20/2017] [Indexed: 11/09/2022] Open
Abstract
We report the magnetic and dielectric behavior of Pb6Ni9(TeO6)5, a new compound comprising the honeycomb-like layers of S = 1 spins, through detailed structural, magnetic and dielectric investigation. An antiferromagnetic-type transition at 25 K (T N ) with weak-ferromagnetic behavior is revealed. Interestingly, a large value of coercive field of 1.32 T at 2 K is observed. The isothermal magnetization after zero-field-cooled condition, it exhibits the presence of large spontaneous exchange bias (SEB) with a magnitude of 0.19 T at 2 K; which is rare in single bulk materials, especially without external doping. The value of |H EB| further enhances to 0.24 T under 16 T field-cooled condition, confirming the presence of large exchange bias in the material.
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Affiliation(s)
- B Koteswararao
- Department of Physics, Indian Institute of Technology Tirupati, TIRUPATI, 517506, India.
- School of Physics, University of Hyderabad, Hyderabad, 500046, India.
| | - Tanmoy Chakrabarty
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400005, India
| | - Tathamay Basu
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400005, India
- Laboratoire CRISMAT, UMR 6508 du CNRS et de l'Ensicaen, 6 Bd Marechal Juin, 14050, Caen, France
| | | | - P V Srinivasarao
- S. S. & N. College, Narasaraopet, Guntur District, Andhra Pradesh, 522601, India
| | - P L Paulose
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400005, India
| | - S Srinath
- School of Physics, University of Hyderabad, Hyderabad, 500046, India.
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Interface-induced spontaneous positive and conventional negative exchange bias effects in bilayer La 0.7Sr 0.3MnO 3/Eu 0.45Sr 0.55MnO 3 heterostructures. Sci Rep 2017; 7:6919. [PMID: 28761051 PMCID: PMC5537235 DOI: 10.1038/s41598-017-07033-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 06/21/2017] [Indexed: 11/25/2022] Open
Abstract
We report zero-field-cooled spontaneous-positive and field-cooled conventional-negative exchange bias effects in epitaxial bilayer composed of La0.7Sr0.3MnO3 (LSMO) with ferromagnetic (FM) and Eu0.45Sr0.55MnO3 (ESMO) with A-type antiferromagnetic (AF) heterostructures respectively. A temperature dependent magnetization study of LSMO/ESMO bilayers grown on SrTiO3 (001) manifest FM ordering (TC) of LSMO at ~320 K, charge/orbital ordering of ESMO at ~194 K and AF ordering (TN) of ESMO at ~150 K. The random field Ising model has demonstrated an interesting observation of inverse dependence of exchange bias effect on AF layer thickness due to the competition between FM-AF interface coupling and AF domain wall energy. The isothermally field induced unidirectional exchange anisotropy formed at the interface of FM-LSMO layer and the kinetically phase-arrested magnetic phase obtained from the metamagnetic AF-ESMO layer could be responsible for the spontaneous exchange bias effect. Importantly, no magnetic poling is needed, as necessary for the applications. The FM-AF interface exchange interaction has been ascribed to the AF coupling with \documentclass[12pt]{minimal}
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\begin{document}$$\sum {J}_{ex}\vec{{S}_{{\rm{FM}}}}\cdot \vec{{S}_{{\rm{AF}}}}$$\end{document}∑JexSFM⃗⋅SAF⃗ (\documentclass[12pt]{minimal}
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\begin{document}$${J}_{ex}\approx {J}_{AF}$$\end{document}Jex≈JAF, coupling constant between AF spins) for the spontaneous positive hysteresis loop shift, and the field-cooled conventional exchange bias has been attributed to the ferromagnetically exchanged interface with \documentclass[12pt]{minimal}
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\begin{document}$${J}_{ex}\approx {J}_{F}$$\end{document}Jex≈JF (coupling constant between FM spins).
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