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Nahar R, Law KM, Roden T, Zengel M, Lewis J, Budhathoki S, Nold R, Avlani H, Akintunde B, Derksen N, Hauser AJ. Dataset on density functional theory investigation of ternary Heusler alloys. Data Brief 2024; 52:109971. [PMID: 38226030 PMCID: PMC10788214 DOI: 10.1016/j.dib.2023.109971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 01/17/2024] Open
Abstract
This paper contains data and results from Density Functional Theory (DFT) investigation of 423 distinct X2YZ ternary full Heusler alloys, where X and Y represent elements from the D-block of the periodic table and Z signifies element from main group. The study encompasses both "regular" and "inverse" Heusler phases of these alloys for a total of 846 potential materials. For each specific alloy and each phase, a range of information is provided including total energy, formation energy, lattice constant, total and site-specific magnetic moments, spin polarization as well as total and projected density of electronic states. The aim of creating this dataset is to provide fundamental theoretical insights into ternary X2YZ Heusler alloys for further theoretical and experimental analysis.
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Affiliation(s)
- Ridwan Nahar
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Ka Ming Law
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Thomas Roden
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Michael Zengel
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Justin Lewis
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Sujan Budhathoki
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Riley Nold
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Harshil Avlani
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Babajide Akintunde
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Naomi Derksen
- Department of Physics and Astronomy, University of Alabama, AL, United States
| | - Adam J. Hauser
- Department of Physics and Astronomy, University of Alabama, AL, United States
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2
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Alves Dos Santos E, França JKP, Dos Santos AO, Nurrieli A, Do Carmo D, Dos Reis RD, Moreira da Silva L. Pressure tuning reverse martensitic transformation in the Mn 0.9Co 0.1NiGe half-Heusler alloy. J Phys Condens Matter 2023; 36:135404. [PMID: 38064751 DOI: 10.1088/1361-648x/ad13d6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/08/2023] [Indexed: 12/29/2023]
Abstract
Here we investigate the structural properties of the Mn0.9Co0.1NiGe half-Heusler alloys under pressure up to 12 GPa by Synchrotron angle-dispersive x-ray diffraction (XRD). At room temperature and pressure, the compound exhibits only the hexagonal NiIn2-type structure. Lowering the temperature to 100 K at ambient pressure induces an almost complete martensitic phase transformation to the orthorhombic TiNiSi-type structure. With increasing pressure, the stable orthorhombic phase gradually undergoes a reverse martensitic transformation. The hexagonal phase reaches 85% of the sample when applying 12 GPa of pressure atT= 100 K. We further evaluated the bulk modulus of both hexagonal and orthorhombic phases and found similar values (123.1 ± 5.9 GPa for hexagonal and 102.8 ± 4.2 GPa for orthorhombic). Also, we show that the lattice contraction induced is anisotropic. Moreover, the high-pressure hexagonal phase shows a volumetric thermal contraction coefficientαv∼ -8.9(1) × 10-5K-1when temperature increases from 100 to 160 K, evidencing a significant negative thermal expansion (NTE) effect. Overall, our results demonstrate that the reverse martensitic transition presented on Mn0.9Co0.1NiGe induced either by pressure or temperature is related to the anisotropic contraction of the crystalline arrangement, which should also play a crucial role in driving the magnetic phase transitions in this system.
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Affiliation(s)
| | | | | | - Andira Nurrieli
- Centro de Ciências de Imperatriz (CCIM), Universidade Federal do Maranhão-UFMA, Maranhão, Brazil
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13053-970, Brazil
| | - Danusa Do Carmo
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13053-970, Brazil
| | - Ricardo Donizeth Dos Reis
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13053-970, Brazil
| | - Luzeli Moreira da Silva
- Centro de Ciências de Imperatriz (CCIM), Universidade Federal do Maranhão-UFMA, Maranhão, Brazil
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Lukashev PV, Wysong J, McFadden S, Baker G, Schmidt B, Shand PM, Kharel P. Electronic, magnetic, and structural properties of NiFeMnAl. J Phys Condens Matter 2023; 36:085801. [PMID: 37918016 DOI: 10.1088/1361-648x/ad08ea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/01/2023] [Indexed: 11/04/2023]
Abstract
Half-metallic Heusler compounds have been extensively studied in the recent years, both experimentally and theoretically, for potential applications in spin-based electronics. Here, we present the results of a combined theoretical and experimental study of the quaternary Heusler compound NiFeMnAl. Our calculations indicate that this material is half-metallic in the ground state and maintains its half-metallic electronic structure under a considerable range of external hydrostatic pressure and biaxial strain. NiFeMnAl crystallizes in the regular cubic Heusler structure, and exhibits ferromagnetic alignment. The practical feasibility of the proposed system is confirmed in the experimental section of this work. More specifically, a bulk ingot of NiFeMnAl was synthesized in A2 type disordered cubic structure using arc melting. It shows a high Curie temperature of about 468 K and a saturation magnetization of 2.3μB/f.u. The measured magnetization value is smaller than the one calculated for the ordered structure. This discrepancy is likely due to the A2 type atomic disorder, as demonstrated by our calculations. We hope that the presented results may be useful for researchers working on practical applications of spin-based electronics.
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Affiliation(s)
- Pavel V Lukashev
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, United States of America
| | - Jax Wysong
- Department of Chemistry, Biochemistry, and Physics, South Dakota State University, Brookings, SD 57007, United States of America
| | - Stephen McFadden
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, United States of America
| | - Gavin Baker
- Department of Chemistry, Biochemistry, and Physics, South Dakota State University, Brookings, SD 57007, United States of America
| | - Brandon Schmidt
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, United States of America
| | - Paul M Shand
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, United States of America
| | - Parashu Kharel
- Department of Chemistry, Biochemistry, and Physics, South Dakota State University, Brookings, SD 57007, United States of America
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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. J Phys Condens Matter 2023; 36:075801. [PMID: 37931322 DOI: 10.1088/1361-648x/ad0a13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Ito T, Xu X, Miyake A, Kinoshita Y, Nagasako M, Takahashi K, Omori T, Tokunaga M, Kainuma R. Pd 2 MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss. Adv Sci (Weinh) 2023; 10:e2207779. [PMID: 37309306 PMCID: PMC10427369 DOI: 10.1002/advs.202207779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/02/2023] [Indexed: 06/14/2023]
Abstract
Metamagnetic shape memory alloys (MMSMAs) are attractive functional materials owing to their unique properties such as magnetostrain, magnetoresistance, and the magnetocaloric effect caused by magnetic-field-induced transitions. However, the energy loss during the martensitic transformation, that is, the dissipation energy, Edis , is sometimes large for these alloys, which limits their applications. In this paper, a new Pd2 MnGa Heusler-type MMSMA with an extremely small Edis and hysteresis is reported. The microstructures, crystal structures, magnetic properties, martensitic transformations, and magnetic-field-induced strain of aged Pd2 MnGa alloys are investigated. A martensitic transformation from L21 to 10M structures is seen at 127.4 K with a small thermal hysteresis of 1.3 K. The reverse martensitic transformation is induced by applying a magnetic field with a small Edis (= 0.3 J mol-1 only) and a small magnetic-field hysteresis (= 7 kOe) at 120 K. The low values of Edis and the hysteresis may be attributed to good lattice compatibility in the martensitic transformation. A large magnetic-field-induced strain of 0.26% is recorded, indicating the proposed MMSMA's potential as an actuator. The Pd2 MnGa alloy with low values of Edis and hysteresis may enable new possibilities for high-efficiency MMSMAs.
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Affiliation(s)
- Tatsuya Ito
- Department of Materials ScienceGraduate School of EngineeringTohoku UniversityAoba‐yama 6‐6‐02Sendai980‐8579Japan
- Present address:
J‐PARC CenterJapan Atomic Energy AgencyShirakata 2‐4Tokai319‐1195Japan
| | - Xiao Xu
- Department of Materials ScienceGraduate School of EngineeringTohoku UniversityAoba‐yama 6‐6‐02Sendai980‐8579Japan
- Organization for Advanced StudiesTohoku UniversityKatahira 2‐1‐1Sendai980‐8577Japan
| | - Atsushi Miyake
- The Institute for Solid State PhysicsThe University of TokyoKashiwanoha 5‐1‐5Kashiwa277‐8581Japan
- Present address:
Institute for Materials ResearchTohoku UniversityKatahira 2‐1‐1Sendai980‐8577Japan
| | - Yuto Kinoshita
- The Institute for Solid State PhysicsThe University of TokyoKashiwanoha 5‐1‐5Kashiwa277‐8581Japan
| | - Makoto Nagasako
- Institute for Materials ResearchTohoku UniversityKatahira 2‐1‐1Sendai980‐8577Japan
| | - Kohki Takahashi
- Institute for Materials ResearchTohoku UniversityKatahira 2‐1‐1Sendai980‐8577Japan
| | - Toshihiro Omori
- Department of Materials ScienceGraduate School of EngineeringTohoku UniversityAoba‐yama 6‐6‐02Sendai980‐8579Japan
| | - Masashi Tokunaga
- The Institute for Solid State PhysicsThe University of TokyoKashiwanoha 5‐1‐5Kashiwa277‐8581Japan
| | - Ryosuke Kainuma
- Department of Materials ScienceGraduate School of EngineeringTohoku UniversityAoba‐yama 6‐6‐02Sendai980‐8579Japan
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Salaheldeen M, Wederni A, Ipatov M, Zhukova V, Zhukov A. Carbon-Doped Co 2MnSi Heusler Alloy Microwires with Improved Thermal Characteristics of Magnetization for Multifunctional Applications. Materials (Basel) 2023; 16:5333. [PMID: 37570037 PMCID: PMC10419722 DOI: 10.3390/ma16155333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 08/13/2023]
Abstract
In the current work, we illustrate the effect of adding a small amount of carbon to very common Co2MnSi Heusler alloy-based glass-coated microwires. A significant change in the magnetic and structure structural properties was observed for the new alloy Co2MnSiC compared to the Co2MnSi alloy. Magneto-structural investigations were performed to clarify the main physical parameters, i.e., structural and magnetic parameters, at a wide range of measuring temperatures. The XRD analysis illustrated the well-defined crystalline structure with average grain size (Dg = 29.16 nm) and a uniform cubic structure with A2 type compared to the mixed L21 and B2 cubic structures for Co2MnSi-based glass-coated microwires. The magnetic behavior was investigated at a temperature range of 5 to 300 K and under an applied external magnetic field (50 Oe to 20 kOe). The thermomagnetic behavior of Co2MnSiC glass-coated microwires shows a perfectly stable behavior for a temperature range from 300 K to 5 K. By studying the field cooling (FC) and field heating (FH) magnetization curves at a wide range of applied external magnetic fields, we detected a critical magnetic field (H = 1 kOe) where FC and FH curves have a stable magnetic behavior for the Co2MnSiC sample; such stability was not found in the Co2MnSi sample. We proposed a phenomenal expression to estimate the magnetization thermal stability, ΔM (%), of FC and FH magnetization curves, and the maximum value was detected at the critical magnetic field where ΔM (%) ≈ 98%. The promising magnetic stability of Co2MnSiC glass-coated microwires with temperature is due to the changing of the microstructure induced by the addition of carbon, as the A2-type structure shows a unique stability in response to variation in the temperature and the external magnetic field. In addition, a unique internal mechanical stress was induced during the fabrication process and played a role in controlling magnetic behavior with the temperature and external magnetic field. The obtained results make Co2MnSiC a promising candidate for magnetic sensing devices based on Heusler glass-coated microwires.
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Affiliation(s)
- Mohamed Salaheldeen
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain; (A.W.); (M.I.); (V.Z.)
- Department of Applied Physics I, EIG, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- Physics Department, Faculty of Science, Sohag University, Sohag 82524, Egypt
- EHU Quantum Center, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
| | - Asma Wederni
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain; (A.W.); (M.I.); (V.Z.)
- Department of Applied Physics I, EIG, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
| | - Mihail Ipatov
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain; (A.W.); (M.I.); (V.Z.)
- Department of Applied Physics I, EIG, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
| | - Valentina Zhukova
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain; (A.W.); (M.I.); (V.Z.)
- Department of Applied Physics I, EIG, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
| | - Arcady Zhukov
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain; (A.W.); (M.I.); (V.Z.)
- Department of Applied Physics I, EIG, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- IKERBASQUE—Basque Foundation for Science, 48011 Bilbao, Spain
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Pathak S, Singh S, Khalid S, Kuga K, Takeuchi T, Bindu R. Orbital hybridisation effects in B2 phase Cr doped Co2MnAl. J Phys Condens Matter 2023. [PMID: 37343572 DOI: 10.1088/1361-648x/ace092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
We investigate here the magnetic, transport, local structural and electronic properties of Co$_2$Mn$_1$$_-$$_x$Cr$_x$Al (x=0, 0.05, 0.1 and 0.2). Our results show that all the compounds stabilise in B2 phase and are ferromagnets. The results reveal disorder at the structural and magnetic levels. X-ray absorption near edge structure (XANES) analysis reveal signature of antisite disorder between Mn and Al atoms with equal ratio. The electronic structure calculations suggest enhancement in the half metallicity, localisation of electrons at the Fermi level and an increment in density of states (DOS) with doping. The combined results of electronic structure calculations and XANES studies suggest transfer of electrons to the Co site. The results of high temperature resistivity measurements suggest the conduction electrons are undergoing transition from delocalisation to weak localisation to activated behaviour with Cr doping. The extended x-ray absorption spectroscopic (EXAFS) analysis shows that the local structure around Mn atom is different from the global structure as obtained from the x-ray diffraction results.The behaviour of the edge region is in line with the trend as obtained from the compositional analysis. We observe link between the hybridisation of 3$\emph{d}$ like states at the Mn, Cr sites with that at the Co site and the transport properties. This could help in understanding the unusual decrement in the lattice parameter with doping. These results reveal the role of local structure in understanding the physical properties of such systems.
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Affiliation(s)
- Swati Pathak
- Indian Institute of Technology Mandi, SBS, Kamand,, Mandi, Himachal Pradesh, 175005, INDIA
| | - Saurabh Singh
- Materials Science and Engineering, The Pennsylvania State University College of Earth and Mineral Sciences, 218 Steidle Building, University Park, Pennsylvania, 16802-2710, UNITED STATES
| | - Syed Khalid
- National Synchrotron Light Source II, National Synchrotron Light Source, National Synchrotron Light Source, Upton, New York, 11973-5000, UNITED STATES
| | - Kentaro Kuga
- Toyota Technological Institute, Japan Science and Technology Agency, Kawaguchi,, Saitama , Aichi, 332-0012, JAPAN
| | - Tsunehiro Takeuchi
- Energy Materials, Toyota Technological Institute, Toyota Technological Institute,Nagoya, Aichi 468-8511, Japan, Nagoya, Aichi, 468-8511, JAPAN
| | - R Bindu
- School of Basic Sciences, Indian Institute of Technology, Kamand Campus, Mandi, Mandi, Himachal Pradesh, 175005, INDIA
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Salaheldeen M, Wederni A, Ipatov M, Zhukova V, Lopez Anton R, Zhukov A. Enhancing the Squareness and Bi-Phase Magnetic Switching of Co 2FeSi Microwires for Sensing Application. Sensors (Basel) 2023; 23:s23115109. [PMID: 37299836 DOI: 10.3390/s23115109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/13/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023]
Abstract
In the current study we have obtained Co2FeSi glass-coated microwires with different geometrical aspect ratios, ρ = d/Dtot (diameter of metallic nucleus, d and total diameter, Dtot). The structure and magnetic properties are investigated at a wide range of temperatures. XRD analysis illustrates a notable change in the microstructure by increasing the aspect ratio of Co2FeSi-glass-coated microwires. The amorphous structure is detected for the sample with the lowest aspect ratio (ρ = 0.23), whereas a growth of crystalline structure is observed in the other samples (aspect ratio ρ = 0.30 and 0.43). This change in the microstructure properties correlates with dramatic changing in magnetic properties. For the sample with the lowest ρ-ratio, non-perfect square loops are obtained with low normalized remanent magnetization. A notable enhancement in the squareness and coercivity are obtained by increasing ρ-ratio. Changing the internal stresses strongly affects the microstructure, resulting in a complex magnetic reversal process. The thermomagnetic curves show large irreversibility for the Co2FeSi with low ρ-ratio. Meanwhile, if we increase the ρ-ratio, the sample shows perfect ferromagnetic behavior without irreversibility. The current result illustrates the ability to control the microstructure and magnetic properties of Co2FeSi glass-coated microwires by changing only their geometric properties without performing any additional heat treatment. The modification of geometric parameters of Co2FeSi glass-coated microwires allows to obtain microwires that exhibit an unusual magnetization behavior that offers opportunities to understand the phenomena of various types of magnetic domain structures, which is essentially helpful for designing sensing devices based on thermal magnetization switching.
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Affiliation(s)
- Mohamed Salaheldeen
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- Department of Applied Physics I, EIG, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- Physics Department, Faculty of Science, Sohag University, Sohag 82524, Egypt
- EHU Quantum Center, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
| | - Asma Wederni
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- Department of Applied Physics I, EIG, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
| | - Mihail Ipatov
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- Department of Applied Physics I, EIG, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
| | - Valentina Zhukova
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- Department of Applied Physics I, EIG, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
| | - Ricardo Lopez Anton
- Department of Applied Physics, Regional Institute for Applied Scientific Research (IRICA), University of Castilla-La Mancha, 13071 Ciudad Real, Spain
| | - Arcady Zhukov
- Department of Polymers and Advanced Materials, Faculty of Chemistry, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- Department of Applied Physics I, EIG, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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9
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Yuce S, Kavak E, Yildirim O, Bruno N, Emre B. Investigation of the inverse magnetocaloric effect with the fraction method. J Phys Condens Matter 2023; 35. [PMID: 37160131 DOI: 10.1088/1361-648x/acd3ce] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/09/2023] [Indexed: 05/11/2023]
Abstract
In this study, we examine Ni49Nb1Mn36In14 (nom. at.%) magnetic shape memory alloy (MSMA) to illustrate the inverse magnetocaloric effect using the fraction method. The magnetic entropy change, ∆S_mag, was calculated with both, the fraction method and the thermomagnetic Maxwell relation. Our results demonstrate that there exists a large magnetization difference between field-cooling and field-heating histories in Ni49Nb1Mn36In14 (nom. at.%) MSMA, which can be attributed to the pinning of lattice entropy and magnetic entropy, as it is well-known that the temperature and applied magnetic fields have an opposing effect on the total entropy change. In addition, we describe the inverse magnetocaloric effect and the contradictory roles on the total entropy change between the two stimuli via the fraction method.
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Affiliation(s)
- Suheyla Yuce
- Ondokuz Mayis University, Körfez, 19 Mayıs Ünv., 55270 Atakum/Samsun, Samsun, Samsun, 55139, TURKEY
| | - E Kavak
- Department of Engineering Physics, Ankara University, Dogol Street, Ankara University, Engineering Faculty, Depart. Eng. Physics, Besevler, Ankara, Turkey, Ankara, 06100, TURKEY
| | - Oguz Yildirim
- Empa Materials Science and Technology, Empa-Swiss Federal Laboratories for Material Science and Technology, CH, 8600, Dübendorf, Switzerland, Dubendorf, 8600, SWITZERLAND
| | - Nickolaus Bruno
- Mechanical Engineering, South Dakota School of Mines and Technology, South Dakota School of Mines and Technology, Department of Mechanical Engineering, Rapid City, SD 57701, USA, Rapid City, South Dakota, 57701-3901, UNITED STATES
| | - Baris Emre
- Department of Engineering Physics Faculty of Engineering, Ankara University, Ankara University, Faculy of Engineering, Department of Physics Engineering, 06100 Tandoğan, Ankara, 06100, TURKEY
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Ren L, Liu L, Song X, Zhao T, Xing X, Feng YP, Chen J, Teo KL. Manipulation of the Topological Ferromagnetic State in a Weyl Semimetal by Spin-Orbit Torque. Nano Lett 2023; 23:3394-3400. [PMID: 37043331 DOI: 10.1021/acs.nanolett.3c00410] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Magnetic Weyl semimetals (MWSMs) exhibit unconventional transport phenomena, such as large anomalous Hall (and Nernst) effects, which are absent in spatial inversion asymmetry WSMs. Compared with its nonmagnetic counterpart, the magnetic state of a MWSM provides an alternative way for the modulation of topology. Spin-orbit torque (SOT), as an effective means of electrically controlling the magnetic states of ferromagnets, may be used to manipulate the topological magnetic states of MWSMs. Here we confirm the MWSM state of high-quality Co2MnGa film by systematically investigating the transport measurements and demonstrating that the magnetization and topology of Co2MnGa can be electrically manipulated. The electrical and magnetic optical measurements further reveal that the current-induced SOT switches the topological magnetic state in a 180-degree manner by applying positive/negative current pulses and in a 90-degree manner by alternately applying two orthogonal current pulses. This work opens up more opportunities for spintronic applications based on topological materials.
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Affiliation(s)
- Lizhu Ren
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Liang Liu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Xiaohe Song
- Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, 119077, Singapore
- Department of Physics, National University of Singapore, 117551, Singapore
| | - Tieyang Zhao
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Xiangjun Xing
- School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 117551, Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Kie Leong Teo
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
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11
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Challab N, Roussigné Y, Chérif SM, Gabor M, Belmeguenai M. Magnetic Damping and Dzyaloshinskii-Moriya Interactions in Pt/Co 2FeAl/MgO Systems Grown on Si and MgO Substrates. Materials (Basel) 2023; 16:1388. [PMID: 36837017 PMCID: PMC9964789 DOI: 10.3390/ma16041388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Spin-pumping-induced damping and interfacial Dzyaloshinskii-Moriya interaction (iDMI) have been studied in Pt/Co2FeAl/MgO systems grown on Si or MgO substrates as a function of Pt and Co2FeAl (CFA) thicknesses. For this, we combined vibrating sample magnetometry (VSM), microstrip ferromagnetic resonance (MS-FMR), and Brillouin light scattering (BLS). VSM measurements of the magnetic moment at saturation per unit area revealed the absence of a magnetic dead layer in both systems, with a higher magnetization at saturation obtained for CFA grown on MgO. The key parameters governing the spin-dependent transport through the Pt/CFA interface, including the spin mixing conductance and the spin diffusion length, have been determined from the CFA and the Pt thickness dependence of the damping. BLS has been used to measure the spin wave non-reciprocity via the frequency mismatch between the Stokes and anti-Stokes lines. iDMI has been separated from the contribution of the interface perpendicular anisotropy difference between Pt/CFA and CFA/MgO. Our investigation revealed that both iDMI strength and spin pumping efficiency are higher for CFA-based systems grown on MgO due to its epitaxial growth confirmed by MS-FMR measurements of the in-plane magnetic anisotropy. This suggests that CFA grown on MgO could be a promising material candidate as a spin injection source via spin pumping and for other spintronic applications.
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Affiliation(s)
- Nabil Challab
- LSPM–CNRS, UPR 3407, Université Sorbonne Paris Nord, F-93430 Villetaneuse, France
| | - Yves Roussigné
- LSPM–CNRS, UPR 3407, Université Sorbonne Paris Nord, F-93430 Villetaneuse, France
| | - Salim Mourad Chérif
- LSPM–CNRS, UPR 3407, Université Sorbonne Paris Nord, F-93430 Villetaneuse, France
| | - Mihai Gabor
- Center for Superconductivity, Spintronics and Surface Science, Physics and Chemistry Department, Technical University of Cluj-Napoca, Str. Memorandumului No. 28, RO-400114 Cluj-Napoca, Romania
| | - Mohamed Belmeguenai
- LSPM–CNRS, UPR 3407, Université Sorbonne Paris Nord, F-93430 Villetaneuse, France
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12
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Talantsev EF. Quantifying Nonadiabaticity in Major Families of Superconductors. Nanomaterials (Basel) 2022; 13:71. [PMID: 36615981 PMCID: PMC9824585 DOI: 10.3390/nano13010071] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
The classical Bardeen−Cooper−Schrieffer and Eliashberg theories of the electron−phonon-mediated superconductivity are based on the Migdal theorem, which is an assumption that the energy of charge carriers, kBTF, significantly exceeds the phononic energy, ℏωD, of the crystalline lattice. This assumption, which is also known as adiabatic approximation, implies that the superconductor exhibits fast charge carriers and slow phonons. This picture is valid for pure metals and metallic alloys because these superconductors exhibit ℏωDkBTF<0.01. However, for n-type-doped semiconducting SrTiO3, this adiabatic approximation is not valid, because this material exhibits ℏωDkBTF≅50. There is a growing number of newly discovered superconductors which are also beyond the adiabatic approximation. Here, leaving aside pure theoretical aspects of nonadiabatic superconductors, we classified major classes of superconductors (including, elements, A-15 and Heusler alloys, Laves phases, intermetallics, noncentrosymmetric compounds, cuprates, pnictides, highly-compressed hydrides, and two-dimensional superconductors) by the strength of nonadiabaticity (which we defined by the ratio of the Debye temperature to the Fermi temperature, TθTF). We found that the majority of analyzed superconductors fall into the 0.025≤TθTF≤0.4 band. Based on the analysis, we proposed the classification scheme for the strength of nonadiabatic effects in superconductors and discussed how this classification is linked with other known empirical taxonomies in superconductivity.
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Affiliation(s)
- Evgueni F. Talantsev
- M. N. Miheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, 18 S. Kovalevskoy Str., 620108 Ekaterinburg, Russia; ; Tel.: +7-912-676-0374
- NANOTECH Centre, Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia
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13
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Dubiel Ł, Stefaniuk I, Wal A. The Low-Field Microwave Absorption in EMR Spectra for Ni 50-xCo xMn 35.5In 14.5 Ribbons. Materials (Basel) 2022; 15:6016. [PMID: 36079398 PMCID: PMC9457258 DOI: 10.3390/ma15176016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/24/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
This paper contains a detailed study of low-field microwave absorption, which is observed in EMR spectra registered for a series of Ni50-xCoxMn35.5In14.5 (x=0,3,5) Heusler alloys polycrystalline in situ and annealed at 1173 K ribbons. The LFMA spectra for all ribbons were performed at X-band (∼9.5 GHz), at temperatures below Curie temperature. Additionally, for annealed Ni45Co5Mn35.5In14.5 ribbons, the LFMA signal dependencies of the external magnetic field modulation amplitude, modulation frequency, microwave power and microwave magnetic field phase were registered. These results confirm the resonant character of LFMA. To determine the basic EMR parameters, such as linewidth and resonance field, the experimental data were fitted by the Dyson function. The LFMA signal is satisfactorily matched by the two lines, and the variability of the component lines with temperature is remarkable.
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Affiliation(s)
- Łukasz Dubiel
- Department of Physics and Medical Engineering, Faculty of Mathematics and Applied Physics, Rzeszow University of Technology, Powstancow Warszawy 12, 35-959 Rzeszow, Poland
| | - Ireneusz Stefaniuk
- Institute of Materials Enginering, College of Natural Sciences, University of Rzeszow, Rejtana 16a, 35-310 Rzeszow, Poland
| | - Andrzej Wal
- Institute of Physics, College of Natural Sciences, University of Rzeszow, Pigonia 1, 35-959 Rzeszow, Poland
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14
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Qiao K, Liang Y, Zuo S, Zhang C, Yu Z, Long Y, Hu F, Shen B, Zhang H. Regulation of Magnetocaloric Effect in Ni 40Co 10Mn 40Sn 10 Alloys by Using a Homemade Uniaxial Strain Pressure Cell. Materials (Basel) 2022; 15:ma15124331. [PMID: 35744390 PMCID: PMC9230806 DOI: 10.3390/ma15124331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/13/2022] [Accepted: 06/16/2022] [Indexed: 01/27/2023]
Abstract
In this study, a homemade uniaxial strain pressure cell was designed to be directly used in the standard magnetometers whereby the magnetic properties of samples subjected to a uniaxial strain and magnetic field were characterized. Its feasibility has been demonstrated by the uniaxial strain control of the phase transition and magnetocaloric effect in Ni40Co10Mn40Sn10 (NCMS) alloys. With the assistance of a uniaxial strain of ~0.5%, the cooling temperature span of NCMS alloys is broadened by 2 K, and the refrigeration capacity under a 3 T magnetic field change increases from 246 to 277 J/kg. This research provides not only direct experimental assistance for the tuning of phase transition by the uniaxial strain but also possibilities for studying the coupled caloric effect in first-order phase transition materials under a combined uniaxial strain and magnetic field by the thermodynamic analysis.
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Affiliation(s)
- Kaiming Qiao
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (K.Q.); (Y.L.); (Z.Y.); (Y.L.)
| | - Yuhang Liang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (K.Q.); (Y.L.); (Z.Y.); (Y.L.)
| | - Shulan Zuo
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
| | - Cheng Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (C.Z.); (F.H.); (B.S.)
| | - Ziyuan Yu
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (K.Q.); (Y.L.); (Z.Y.); (Y.L.)
| | - Yi Long
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (K.Q.); (Y.L.); (Z.Y.); (Y.L.)
| | - Fengxia Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (C.Z.); (F.H.); (B.S.)
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (C.Z.); (F.H.); (B.S.)
| | - Hu Zhang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (K.Q.); (Y.L.); (Z.Y.); (Y.L.)
- Correspondence: ; Tel.: +86-010-62333733
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16
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Yin H, Du A. Revealing the Potential of Ternary Medium-Entropy Alloys as Exceptional Electrocatalysts toward Nitrogen Reduction: An Example of Heusler Alloys. ACS Appl Mater Interfaces 2022; 14:15235-15242. [PMID: 35332777 DOI: 10.1021/acsami.2c00210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
With less energy consumption and environmental pollution, electrochemical ammonia synthesis is regarded as the most promising way to replace the industrial Haber-Bosch process, which greatly contributes to global energy consumption and CO2 emission. At present, the best metal electrocatalyst for N2 fixation is ruthenium although its performance still suffers from a low Faradaic efficiency and a high overpotential. Alloy engineering is a promising way to discover more metal-based electrocatalysts for dinitrogen reduction reaction (N2RR), and almost all reported alloy catalysts so far are binary alloys. In this work, we proposed a large group of ternary alloy electrocatalysts (Heusler alloys) for N2RR and demonstrated their superior catalytic performance. As an example, alloying Ru with Mn and Si led to a reduced Ru-Ru distance on the surface, which facilitates an uncommon horizontal adsorption mode of N2 and results in effective activation of N2 molecules. The theoretical overpotential of N2RR on Ru2MnSi(100-Ru) is only around 0.28 V, which ranks among the best reported results, and the usage of precious Ru is greatly reduced. Meanwhile, the adsorption of N2 on Ru2MnSi(100-Ru) was much stronger than that of protons, and it also took less energy to drive N2RR than the hydrogen evolution reaction (HER), making HER less competitive on this catalyst. Considering the successful synthesis of numerous Heusler alloys including the six members mentioned here, our work provided a wider range of practical and excellent N2RR electrocatalysts in terms of both catalytic performance and economical cost.
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Affiliation(s)
- Hanqing Yin
- School of Chemistry and Physics, Queensland University of Technology, Gardens Point Campus, Brisbane 4001, Australia
- QUT Centre for Materials Science, Queensland University of Technology, Gardens Point Campus, Brisbane 4001, Australia
| | - Aijun Du
- School of Chemistry and Physics, Queensland University of Technology, Gardens Point Campus, Brisbane 4001, Australia
- QUT Centre for Materials Science, Queensland University of Technology, Gardens Point Campus, Brisbane 4001, Australia
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17
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Cháb V, Drchal V, Máca F, Kudrnovský J, Cichoň S, Lančok J, Heczko O. Effect of Twinning on Angle-Resolved Photoemission Spectroscopy Analysis of Ni 49.7Mn 29.1Ga 21.2(100) Heusler Alloy. Materials (Basel) 2022; 15:ma15030717. [PMID: 35160661 PMCID: PMC8837013 DOI: 10.3390/ma15030717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 02/01/2023]
Abstract
To explain the observed features of k-space photoelectron images taken on off-stoichiometric Heusler Ni49.7Mn29.1Ga21.2 single-crystals in the cubic austenitic and pseudotetragonal martensitic phases, the images were simulated theoretically. Despite the moderate structural difference of both phases, there is large difference in photoemission spectra. Analysis of the final states' structure, matrix elements, and interface barrier scattering was performed to interpret discrepancies between the external photoemission of the austenite and martensite. The missing signal at the surface-normal emission of the martensitic phase is, ultimately, explained by repeated scatterings of escaping electrons on the interfaces between nanotwins.
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18
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Midhunlal PV, Venkatesh C, Chelvane JA, Babu PD, Kumar NH. Neutron diffraction and ab initiostudies on the fully compensated ferrimagnetic characteristics of Mn 2V 1-xCo xGa Heusler alloys. J Phys Condens Matter 2022; 34:125801. [PMID: 34933284 DOI: 10.1088/1361-648x/ac4532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Neutron diffraction andab initiostudies were carried out on Mn2V1-xCoxGa (x= 0, 0.25, 0.5, 0.75, 1) Heusler alloys which exhibits highTCfully compensated ferrimagnetic characteristics forx= 0.5. A combined analysis of neutron diffraction andab initiocalculations revealed the crystal structure and magnetic configuration which could not be determined from the x-ray diffraction and magnetic measurements. As reported earlier, Rietveld refinement of neutron diffraction data confirmedL21structure for Mn2VGa andXastructure for Mn2CoGa. The alloys withx= 0.25 and 0.5 possessL21structure with Mn(C)-Co disorder. As the Co concentration reaches 0.75, a structural transition has been observed from disorderedL21to disorderedXa. Detailedab initiostudies also confirmed this structural transition. The reason for the magnetic moment compensation in Mn2(V1-xCox)Ga was identified to be different from that of the earlier reported fully compensated ferrimagnet (MnCo)VGa. With the help of neutron diffraction andab initiostudies, it is identified that the disorderedL21structure with antiparallel coupling between the ferromagnetically aligned magnetic moments of (Mn(A)-Mn(C)) and (V-Co) atom pairs enables the compensation in Mn2V1-xCoxGa.
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Affiliation(s)
- P V Midhunlal
- Department of Physics, Indian Institute of Technology Madras, Chennai-600036, India
- Department of Physics, Faculty of Engineering & Technology, JAIN (Deemed-to-be University), Bangalore-562112, India
| | - C Venkatesh
- Saha Institute of Nuclear Physics, Bidhannagar, Kolkata, West Bengal-700064, India
| | - J Arout Chelvane
- Defence Metallurgical Research Laboratory, Kanchanbagh (PO), Hyderabad-500058, India
| | - P D Babu
- UGC-DAE Consortium for Scientific Research, Mumbai Center, R-5 shed, BARC, Trombay, Mumbai-400085, India
| | - N Harish Kumar
- Department of Physics, Indian Institute of Technology Madras, Chennai-600036, India
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19
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Dubiel Ł, Wal A, Stefaniuk I, Żywczak A, Potera P, Maziarz W. Cobalt Content Effect on the Magnetic Properties of Ni 50-xCo xMn 35.5In 14.5 Annealed Ribbons. Materials (Basel) 2021; 14:ma14195497. [PMID: 34639892 PMCID: PMC8509712 DOI: 10.3390/ma14195497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/16/2022]
Abstract
We present a study of the annealing effect and its influence on magnetic and structural properties for a series of Heusler alloys Ni50−xCoxMn35.5In14.5 (x=0,3,5) prepared in ribbon form. We studied the morphology and composition using scanning electron microscopy (SEM) equipped with an X-ray microanalyzer (EDX). The magnetic properties were determined by two methods: electron magnetic resonance (EMR) and vibrating sample magetometer (VSM). We found that cobalt content in the annealed samples reveals an additional magnetic phase transition at lower temperatures.
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Affiliation(s)
- Łukasz Dubiel
- Department of Physics and Medical Engineering, Faculty of Mathematics and Applied Physics, Rzeszow University of Technology, Powstancow Warszawy 12, 35-959 Rzeszow, Poland
- Correspondence:
| | - Andrzej Wal
- Institute of Physics, College of Natural Sciences, University of Rzeszow, Pigonia 1, 35-959 Rzeszow, Poland; (A.W.); (P.P.)
| | - Ireneusz Stefaniuk
- Center of Teaching Technical and Natural Sciences, University of Rzeszow, Pigonia 1, 35-959 Rzeszow, Poland;
| | - Antoni Żywczak
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, A. Mickiewicza 30, 30-059 Krakow, Poland;
| | - Piotr Potera
- Institute of Physics, College of Natural Sciences, University of Rzeszow, Pigonia 1, 35-959 Rzeszow, Poland; (A.W.); (P.P.)
| | - Wojciech Maziarz
- Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Reymonta 25, 30-059 Krakow, Poland;
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20
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Khunkitti P, Siritaratiwat A, Pituso K. Free Layer Thickness Dependence of the Stability in Co 2(Mn 0.6Fe 0.4)Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in 2. Micromachines (Basel) 2021; 12:mi12091010. [PMID: 34577654 PMCID: PMC8467614 DOI: 10.3390/mi12091010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/22/2021] [Accepted: 08/24/2021] [Indexed: 11/28/2022]
Abstract
Current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) read sensors based on Heusler alloys are promising candidates for ultrahigh areal densities of magnetic data storage technology. In particular, the thickness of reader structures is one of the key factors for the development of practical CPP-GMR sensors. In this research, we studied the dependence of the free layer thickness on the stability of the Co2(Mn0.6Fe0.4)Ge Heusler-based CPP-GMR read head for an areal density of 1 Tb/in2, aiming to determine the appropriate layer thickness. The evaluations were done through simulations based on micromagnetic modelling. The reader stability indicators, including the magnetoresistance (MR) ratio, readback signal, dibit response asymmetry parameter, and power spectral density profile, were characterized and discussed. Our analysis demonstrates that the reader with a free layer thickness of 3 nm indicates the best stability performance for this particular head. A reasonably large MR ratio of 26% was obtained by the reader having this suitable layer thickness. The findings can be utilized to improve the design of the CPP-GMR reader for use in ultrahigh magnetic recording densities.
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Affiliation(s)
- Pirat Khunkitti
- KKU-Seagate Cooperation Research Laboratory, Department of Electrical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002, Thailand;
- Correspondence: ; Tel.: +66-86-636-5678
| | - Apirat Siritaratiwat
- KKU-Seagate Cooperation Research Laboratory, Department of Electrical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002, Thailand;
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21
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Kutynia K, Gębara P. Tuning of the Structure and Magnetocaloric Effect of Mn 1-xZr xCoGe Alloys (Where x = 0.03, 0.05, 0.07, and 0.1). Materials (Basel) 2021; 14:3129. [PMID: 34200381 DOI: 10.3390/ma14113129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 11/27/2022]
Abstract
The aim of the present work is to study the influence of a partial substitution of Mn by Zr in MnCoGe alloys. The X-ray diffraction (XRD) studies revealed a coexistence of the orthorhombic TiNiSi-type and hexagonal Ni2In- type phases. The Rietveld analysis showed that the changes in lattice constants and content of recognized phases depended on the Zr addition. The occurrence of structural transformation was detected. This transformation was confirmed by analysis of the temperature dependence of exponent n given in the relation ΔSM = C·(BMAX)n. A decrease of the Curie temperature with an increase of the Zr content in the alloy composition was detected. The magnetic entropy changes were 6.93, 13.42, 3.96, and 2.94 J/(kg K) for Mn0.97Zr0.03CoGe, Mn0.95Zr0.05CoGe, Mn0.93Zr0.07CoGe, and Mn0.9Zr0.1CoGe, respectively. A significant rise in the magnetic entropy change for samples doped by Zr (x = 0.05) was caused by structural transformation.
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Silva LEL, Patiño JC, Gomes AM. On the structural and thermo-magnetic study of the magnetocaloric Heusler alloy Ni 2Mn 1-xCu xGa 0.8Al 0.2. J Phys Condens Matter 2021; 33:235701. [PMID: 33618341 DOI: 10.1088/1361-648x/abe89f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Full Heusler alloys present martensitic transition and shape memory effect related phenomena and several technological applications can be envisaged. One promising area is the magnetocaloric effect (MCE) as the magnetic and structural transitions combine to produce a large isothermal entropy and adiabatic temperature change useful for heating and cooling applications. In this work, we study a Ni-(Mn, Cu)-(Ga, Al) Heusler alloy family which has a giant MCE when the chemical composition is fine-tuned to bring the temperature of the second-order magnetic transition close the first-order structural one. Our results show that, for a certain range of copper concentration, the samples show interesting physical properties captured by calorimetric, microscopy imaging, and magnetization measurements, leading to a high MCE with minimized hysteresis.
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Affiliation(s)
- L E L Silva
- Instituto de Física, Departamento de Física dos Sólidos, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - J C Patiño
- Instituto de Física, Departamento de Física dos Sólidos, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - A M Gomes
- Instituto de Física, Departamento de Física dos Sólidos, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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23
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Vovk A, Bunyaev SA, Štrichovanec P, Vovk NR, Postolnyi B, Apolinario A, Pardo JÁ, Algarabel PA, Kakazei GN, Araujo JP. Control of Structural and Magnetic Properties of Polycrystalline Co 2FeGe Films via Deposition and Annealing Temperatures. Nanomaterials (Basel) 2021; 11:nano11051229. [PMID: 34066968 PMCID: PMC8148587 DOI: 10.3390/nano11051229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/25/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022]
Abstract
Thin polycrystalline Co2FeGe films with composition close to stoichiometry have been fabricated using magnetron co-sputtering technique. Effects of substrate temperature (TS) and post-deposition annealing (Ta) on structure, static and dynamic magnetic properties were systematically studied. It is shown that elevated TS (Ta) promote formation of ordered L21 crystal structure. Variation of TS (Ta) allow modification of magnetic properties in a broad range. Saturation magnetization ~920 emu/cm3 and low magnetization damping parameter α ~ 0.004 were achieved for TS = 573 K. This in combination with soft ferromagnetic properties (coercivity below 6 Oe) makes the films attractive candidates for spin-transfer torque and magnonic devices.
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Affiliation(s)
- Andrii Vovk
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
- Correspondence:
| | - Sergey A. Bunyaev
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
| | - Pavel Štrichovanec
- Instituto de Nanociencia y Materiales de Aragón, Campus Río Ebro, Universidad de Zaragoza—CSIC, 50018 Zaragoza, Spain; (P.Š.); (J.Á.P.)
| | - Nikolay R. Vovk
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
| | - Bogdan Postolnyi
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
- Department of Nanoelectronics and Surface Modification, Sumy State University, 40007 Sumy, Ukraine
| | - Arlete Apolinario
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
| | - José Ángel Pardo
- Instituto de Nanociencia y Materiales de Aragón, Campus Río Ebro, Universidad de Zaragoza—CSIC, 50018 Zaragoza, Spain; (P.Š.); (J.Á.P.)
- Departamento de Ciencia y Tecnología de Materiales y Fluidos, Universidad de Zaragoza, 50018 Zaragoza, Spain
| | - Pedro Antonio Algarabel
- Instituto de Nanociencia y Materiales de Aragón, Campus San Francisco, Universidad de Zaragoza—CSIC, 50009 Zaragoza, Spain;
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Gleb N. Kakazei
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
| | - João Pedro Araujo
- Departamento de Física e Astronomia, Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Universidade do Porto, 4169-007 Porto, Portugal; (S.A.B.); (N.R.V.); (B.P.); (A.A.); (G.N.K.); (J.P.A.)
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Guo J, Zhong M, Zhou W, Zhang Y, Wu Z, Li Y, Zhang J, Liu Y, Yang H. Grain Size Effect of the γ Phase Precipitation on Martensitic Transformation and Mechanical Properties of Ni-Mn-Sn-Fe Heusler Alloys. Materials (Basel) 2021; 14:2339. [PMID: 33946375 DOI: 10.3390/ma14092339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 11/16/2022]
Abstract
Isothermal annealing of a eutectic dual phase Ni-Mn-Sn-Fe alloy was carried out to encourage grain growth and investigate the effects of grain size of the γ phase on the martensitic transformation behaviour and mechanical properties of the alloy. It is found that with the increase of the annealing time, the grain size and volume fraction of the γ phase both increased with the annealing time predominantly by the inter-diffusion of Fe and Sn elements between the γ phase and the Heusler matrix. The isothermal anneals resulted in the decrease of the e/a ratio and suppression of the martensitic transformation of the matrix phase. The fine γ phase microstructure with an average grain size of 0.31 μm showed higher fracture strength and ductility values by 28% and 77% compared to the coarse-grained counterpart with an average grain size of 3.31 μm. The fine dual phase microstructure shows a quasi-linear superelasticity of 4.2% and very small stress hysteresis during cyclic loading, while the coarse dual phase counterpart presents degraded superelasticity of 2.6% and large stress hysteresis. These findings indicate that grain size refinement of the γ phase is an effective approach in improving the mechanical and transformation properties of dual phase Heusler alloys.
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Wu M, Zhou F, Khenata R, Kuang M, Wang X. Phase Transition and Electronic Structures of All- d-Metal Heusler-Type X 2MnTi Compounds (X = Pd, Pt, Ag, Au, Cu, and Ni). Front Chem 2020; 8:546947. [PMID: 33363101 PMCID: PMC7759634 DOI: 10.3389/fchem.2020.546947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/21/2020] [Indexed: 11/13/2022] Open
Abstract
In this work, we investigated the phase transition and electronic structures of some newly designed all-d-metal Heusler compounds, X2MnTi (X = Pd, Pt, Ag, Au, Cu, and Ni), by means of the first principles. The competition between the XA and L21 structures of these materials was studied, and we found that X2MnTi favors to feature the L21-type structure, which is consistent with the well-known site-preference rule (SPR). Under the L21 structure, we have studied the most stable magnetic state of these materials, and we found that the ferromagnetic state is the most stable due to its lower energy. Through tetragonal deformation, we found that the L21 structure is no longer the most stable structure, and a more stable tetragonal L10 structure appeared. That is, under the tetragonal strain, the material enjoys a tetragonal phase transformation (i.e., from cubic L21 to tetragonal L10 structure). This mechanism of L21-L10 structure transition is discussed in detail based on the calculated density of states. Moreover, we found that the energy difference between the most stable phases of L10 and L21, defined as ΔE M (ΔE M = E Cubic-E Tetragonal), can be adjusted by the uniform strain. Finally, the phonon spectra of all tetragonal X2MnTi (X = Pd, Pt, Ag, Au, Cu, and Ni) phases are exhibited, which provides a powerful evidence for the stability of the tetragonal L10 state. We hope that our research can provide a theoretical guidance for future experimental investigations.
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Affiliation(s)
- Mengxin Wu
- School of Physical Science and Technology, Southwest University, Chongqing, China
| | - Feng Zhou
- School of Physical Science and Technology, Southwest University, Chongqing, China
| | - Rabah Khenata
- Laboratoire de Physique Quantique de la Matière et de la Modélisation Mathématique (LPQ3M), Université de Mascara, Mascara, Algeria
| | - Minquan Kuang
- School of Physical Science and Technology, Southwest University, Chongqing, China
| | - Xiaotian Wang
- School of Physical Science and Technology, Southwest University, Chongqing, China
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26
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Dutt R, Pandey D, Chakrabarti A. Probing the martensite transition and thermoelectric properties of Co xTa Z( Z=Si, Ge, Sn and x=1, 2): a study based on density functional theory. J Phys Condens Matter 2020; 33:045402. [PMID: 33146151 DOI: 10.1088/1361-648x/abbb40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
In this work, using density functional theory based electronic structure calculations, we carry out a comparative study of geometric, mechanical, electronic, magnetic, and thermoelectric properties of CoxTaZalloys, whereZ= Si, Ge and Sn andx= 1 and 2. In the present study, a systematic approach has been taken to perform calculations to probe the possibility of existence of a tetragonal (martensite) phase in these alloys and also to perform a comparative study of various physical properties of the six systems, mentioned above, in the cubic and possible tetragonal phases. From our calculations, a tetragonal phase has been found to be stable up to about 400 K in case of Co2TaSi and Co2TaGe alloys, and up to about 115 K for Co2TaSn, indicating the presence of room temperature cubic phase in the latter alloy unlike the former two. Further, the results based on the energetics and electronic structure have been found to corroborate well with the elastic properties. All the above-mentioned full Heusler alloys (FHAs) show magnetic behavior with metallicity in both the phases. However, their half Heusler counterparts exhibit non-magnetic semi-conducting behavior in the cubic phase. We calculate and compare the thermoelectric properties, in detail, of all the materials in the cubic and possible tetragonal phases. In the cubic phase, the half Heusler alloys exhibit improved thermoelectric properties compared to the respective FHAs. Furthermore, it is observed that the FHAs exhibit higher (by about an order of magnitude) values of Seebeck coefficients in their cubic phases, compared to those in the tetragonal phases (which are of the order of only a few micro-volts/Kelvin). The observed behaviors of the transport properties of the probed materials have been analyzed using the topology of the Fermi surface.
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Affiliation(s)
- Rajeev Dutt
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India
- Theory and Simulations Laboratory, Human Resources Development Section, Raja Ramanna Centre for Advanced Technology, Indore-452013, India
| | - Dhanshree Pandey
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India
- Theory and Simulations Laboratory, Human Resources Development Section, Raja Ramanna Centre for Advanced Technology, Indore-452013, India
| | - Aparna Chakrabarti
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India
- Theory and Simulations Laboratory, Human Resources Development Section, Raja Ramanna Centre for Advanced Technology, Indore-452013, India
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27
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Lünser K, Diestel A, Nielsch K, Fähler S. Influencing Martensitic Transition in Epitaxial Ni-Mn-Ga-Co Films with Large Angle Grain Boundaries. Materials (Basel) 2020; 13:E3674. [PMID: 32825317 DOI: 10.3390/ma13173674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/11/2020] [Accepted: 08/14/2020] [Indexed: 11/17/2022]
Abstract
Magnetocaloric materials based on field-induced first order transformations such as Ni-Mn-Ga-Co are promising for more environmentally friendly cooling. Due to the underlying martensitic transformation, a large hysteresis can occur, which in turn reduces the efficiency of a cooling cycle. Here, we analyse the influence of the film microstructure on the thermal hysteresis and focus especially on large angle grain boundaries. We control the microstructure and grain boundary density by depositing films with local epitaxy on different substrates: Single crystalline MgO(0 0 1), MgO(1 1 0) and Al2O3(0 0 0 1). By combining local electron backscatter diffraction (EBSD) and global texture measurements with thermomagnetic measurements, we correlate a smaller hysteresis with the presence of grain boundaries. In films with grain boundaries, the hysteresis is decreased by about 30% compared to single crystalline films. Nevertheless, a large grain boundary density leads to a broadened transition. To explain this behaviour, we discuss the influence of grain boundaries on the martensitic transformation. While grain boundaries act as nucleation sites, they also lead to different strains in the material, which gives rise to various transition temperatures inside one film. We can show that a thoughtful design of the grain boundary microstructure is an important step to optimize the hysteresis.
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28
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Ahmad A, Srivastava SK, Das AK. Phase stability and the effect of lattice distortions on electronic properties and half-metallic ferromagnetism of Co 2FeAl Heusler alloy: an ab initiostudy. J Phys Condens Matter 2020; 32:415606. [PMID: 32575089 DOI: 10.1088/1361-648x/ab9f4f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Density functional theory calculations within the generalized gradient approximation are employed to study the ground state of Co2FeAl. Various magnetic configurations are considered to find out its most stable phase. The ferromagnetic ground state of the Co2FeAl is energetically observed with an optimized lattice constant of 5.70 Å. After that, the system was subjected under uniform and non-uniform strains, to see their effects on spin polarization (P) and half-metallicity. The effect of spin-orbit coupling is considered in the present study. Half-metallicity (and 100%P) is retained only under uniform strains started from 0 to +4%, and dropped rapidly from 90% to 16% for the negative strains started from -1% to -6%. We find that the present system is much sensitive under tetragonal distortions as half-metallicity (and 100%P) is preserved only for the cubic case. The main reason for the loss of half-metallicity is due to the shift of the bands with respect to the Fermi level (EF). We also discuss the influence of these results on spintronics devices.
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Affiliation(s)
- Aquil Ahmad
- Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - S K Srivastava
- Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - A K Das
- Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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29
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Jena RP, Kumar D, Lakhani A. Scaling analysis of anomalous Hall resistivity in the Co 2TiAl Heusler alloy. J Phys Condens Matter 2020; 32:365703. [PMID: 32369785 DOI: 10.1088/1361-648x/ab9055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
A comprehensive magnetotransport study including resistivity (ρxx), isothermal magnetoresistance, Hall resistivity (ρxy) and magnetization have been carried out at different temperatures on the Co2TiAl Heusler alloy. Co2TiAl alloy shows a paramagnetic to ferromagnetic (FM) transition below the Curie temperature (TC) ∼ 125 K. In the FM region, resistivity and magnetoresistance reveal a spin flip electron-magnon scattering and the Hall resistivity unveils the anomalous Hall resistivity. Scaling of anomalous Hall resistivity with resistivity establishes the extrinsic scattering process responsible for the anomalous Hall resistivity; however skew scattering is the dominant mechanism compared to the side-jump contribution. A one to one correspondence between magnetoresistance and side-jump contribution to anomalous Hall resistivity verifies the electron-magnon scattering being the source of side-jump contribution to the anomalous Hall resistivity.
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Affiliation(s)
- Rudra Prasad Jena
- UGC-DAE Consortium for Scientific Research, Devi Ahilya University Campus, Khandwa Road, Indore-452001, M.P., India
| | - Devendra Kumar
- UGC-DAE Consortium for Scientific Research, Devi Ahilya University Campus, Khandwa Road, Indore-452001, M.P., India
| | - Archana Lakhani
- UGC-DAE Consortium for Scientific Research, Devi Ahilya University Campus, Khandwa Road, Indore-452001, M.P., India
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Hari SR, Srinivas V, Li CR, Kuo YK. Thermoelectric properties of rare-earth doped Fe 2VAl Heusler alloys. J Phys Condens Matter 2020; 32:355706. [PMID: 32353843 DOI: 10.1088/1361-648x/ab8ec6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
The low-temperature electrical transport properties of the rare-earth (RE) Ce, Dy, Sm element doped Fe2VAl Heusler alloys have been investigated. A significant enhancement in the Seebeck coefficientS(peak values of about -125 to -160μV K-1) is observed as compared to the pure Fe2VAl (peak value of about 40μV K-1). It is observed that the thermal conductivity reduced by 50% in RE-doped samples. The single parabolic band model has been used to analyze the experimental data and to understand the role of fundamental parameters like the Lorenz number. The lattice contribution to the total thermal conductivity was analyzed through the Callaway model, which in turn provided the insight into the phonon scattering in these alloys. Finally, we demonstrate a significant improvement in power factor and figure of merit at all temperatures for the RE-doped Fe2VAl alloys.
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Affiliation(s)
- Sudhakara Rao Hari
- Department of Physics, Indian Institute of Technology Madras, Chennai, India
| | - V Srinivas
- Department of Physics, Indian Institute of Technology Madras, Chennai, India
| | - C R Li
- Department of Physics, National Dong Hwa University, Taiwan
| | - Y K Kuo
- Department of Physics, National Dong Hwa University, Taiwan
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Muhammad I, Zhang JM, Ali A, Mushtaq M, Muhammad S. Stable half-metallicity in the (001)-oriented thin films of Co-doped full- Heusler alloys Ti 2Fe 1-xCo xSn ( x=0.00, 0.25, 0.50, 0.75 or 1.00). J Phys Condens Matter 2020; 32:325001. [PMID: 32209744 DOI: 10.1088/1361-648x/ab832d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 03/25/2020] [Indexed: 06/10/2023]
Abstract
Thin films with stable half-metallic (HM) character and 100% spin-polarization (SP) are required to be used in spintronic devices. The HM character has been predicted theoretically in many Heusler alloys thin films and confirmed by experiments. Full-Heusler alloy Ti2FeSn has been studied extensively. It has been reported that their (001)-oriented thin films with TiFe or TiSn terminations preserve 100% SP, but the HM character is unstable because the edge of the bandgap is closed to the Fermi levelEF. Therefore, we investigate the effects of the Co-doping on the structural, electronic and magnetic properties of the bulk full-Heusler alloys Ti2Fe1-xCoxSn (x= 0.00, 0.25, 0.50, 0.75 or 1.00) and their (001)-oriented thin films. The bulk Ti2Fe1-xCoxSn (x= 0.00, 0.25, 0.50, 0.75 or 1.00) alloys are all HM ferromagnets. We investigate twelve possible terminations and show that five of them preserve HM character with 100% SP at the Fermi levelEF, while in the remaining seven, surface states emerge in the spin-down channel at the Fermi levelEF, significantly reducing their SP. The Co-doping significantly increases the stability of the TiSn slab, also increases its spin-down bandgapEg↓and HM gapEgHMatx= 0.50. The stable HM character makes it is a slab of maximum benefit in the applications of spintronic devices, especially in magnetic tunnel junctions.
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Affiliation(s)
- Iltaf Muhammad
- College of Physics and Information Technology, Shaanxi Normal University, Xian 710119, Shaanxi, People's Republic of China
| | - Jian-Min Zhang
- College of Physics and Information Technology, Shaanxi Normal University, Xian 710119, Shaanxi, People's Republic of China
| | - Anwar Ali
- College of Physics and Information Technology, Shaanxi Normal University, Xian 710119, Shaanxi, People's Republic of China
| | - Muhammad Mushtaq
- Department of Physics, Women University of Azad Jammu & Kashmir, Bagh, 12500, Pakistan
| | - Suleman Muhammad
- Department of Physics, Abdul Wali Khan University, Mardan 23200, KPK, Pakistan
- School of Materials Science & Engineering, Nanjing University of Science & Technology, Nanjing 210094, People's Republic of China
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32
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Takhsha Ghahfarokhi M, Nasi L, Casoli F, Fabbrici S, Trevisi G, Cabassi R, Albertini F. Following the Martensitic Configuration Footprints in the Transition Route of Ni-Mn-Ga Magnetic Shape Memory Films: Insight into the Role of Twin Boundaries and Interfaces. Materials (Basel) 2020; 13:ma13092103. [PMID: 32370074 PMCID: PMC7254361 DOI: 10.3390/ma13092103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/26/2020] [Accepted: 04/28/2020] [Indexed: 11/25/2022]
Abstract
Magnetic shape memory Heuslers have a great potential for their exploitation in next-generation cooling devices and actuating systems, due to their “giant” caloric and thermo/magnetomechanical effects arising from the combination of magnetic order and a martensitic transition. Thermal hysteresis, broad transition range, and twinning stress are among the major obstacles preventing the full exploitation of these materials in applications. Using Ni-Mn-Ga seven-modulated epitaxial thin films as a model system, we investigated the possible links between the phase transition and the details of the twin variants configuration in the martensitic phase. We explored the crystallographic relations between the martensitic variants from the atomic-scale to the micro-scale through high-resolution techniques and combined this information with the direct observation of the evolution of martensitic twin variants vs. temperature. Based on our multiscale investigation, we propose a route for the martensitic phase transition, in which the interfaces between different colonies of twins play the major role of initiators for both the forward and reverse phase transition. Linking the martensitic transition to the martensitic configuration sheds light onto the possible mechanisms influencing the transition and paves the way towards microstructure engineering for the full exploitation of shape memory Heuslers in different applications.
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33
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Mushtaq M, Muhammad I, Ali A, Sattar MA, Muhammad S. First-principles search for half-metallic ferromagnetism in CsCrZ 2 (Z = O, S, Se or Te) Heusler alloys. J Mol Graph Model 2020; 98:107620. [PMID: 32311661 DOI: 10.1016/j.jmgm.2020.107620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 03/30/2020] [Accepted: 04/07/2020] [Indexed: 10/24/2022]
Abstract
Exploring highly spin-polarized materials is crucial for the development of spin-based devices. In this paper, we investigate the atomic structure, electronic, half-metallic and magnetic properties of the CsCrZ2 (Z = O, S, Se or Te) Heusler alloys, by performing first-principles calculations based on density functional theory (DFT). The geometry optimization process shows that the alloys are more stable in Cu2MnAl type structure than in Hg2CuTi one. To find a magnetic ground state, the total energy of the alloys is calculated in the non-magnetic (NM), ferromagnetic (FM) and anti-ferromagnetic (AFM) ordering. We find that, the FM ordering yields the lowest energy, thereby confirming that the alloys are FM in the ground state. On computing the cohesive and formation energy in the ground state, it is found that alloys are chemically and thermodynamically stable, respectively. Spin polarized band structures and density of states (DOS) demonstrate that the CsCrO2, CsCrS2 and CsCrSe2 alloys are true half-metals with 100% spin-polarization at the Fermi level, while the CsCrTe2 alloy is predicted as highly spin polarized material. Furthermore, the CsCrO2, CsCrS2 and CsCrSe2 alloys possess 2.529, 2.250 and 2.050 eV gaps in the spin down band structure, respectively. The calculated total magnetic moments reveal that half-metallic alloys have an integral total magnetic moment of 3.000 μB, which satisfies the Slater-Pauling rule Mt = Zt-16. The main contribution to the total magnetic moment comes from the Cr atoms (about 3.9 μB). Furthermore, the Curie temperature TC calculated within classical Heisenberg model is estimated to be about 822 K (CsCrO2), 685 K (CsCrS2), 753 K (CsCrSe2) and 636 K (CsCrTe2). The obtained high spin polarization and above room temperature FM ordering make the materials as promising materials to be used in spintronic technology.
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Affiliation(s)
- Muhammad Mushtaq
- Department of Physics, College of Science, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Iltaf Muhammad
- College of Physics and Information Technology, Shaanxi Normal University, Xian, 710119, Shaanxi, PR China.
| | - Anwar Ali
- College of Physics and Information Technology, Shaanxi Normal University, Xian, 710119, Shaanxi, PR China
| | - Muhammad Atiff Sattar
- Department of Physics, College of Science, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Suleman Muhammad
- Department of Physics, Abdul Wali Khan University, Mardan, 23200, KPK, Pakistan; School of Materials Science & Engineering, Nanjing University of Science & Technology, Nanjing, 210094, PR China
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Zhang YJ, Liu ZH, Wu ZG, Ma XQ. Prediction of fully compensated ferrimagnetic spin-gapless semiconducting FeMnGa/Al/In half Heusler alloys. IUCrJ 2019; 6:610-618. [PMID: 31316805 PMCID: PMC6608636 DOI: 10.1107/s2052252519005062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 04/13/2019] [Indexed: 06/10/2023]
Abstract
Materials with full spin polarization that exhibit zero net magnetization attract great scientific interest because of their potential applications in spintronics. Here, the structural, magnetic and electronic properties of a C1 b -ordered FeMnGa alloy are reported using first-principles calculations. The results indicate that the corresponding band structure exhibits a considerable gap in one of the spin channels and a zero gap in the other thus allowing for high mobility of fully spin-polarized carriers. The localized magnetic moments of Fe and Mn atoms have an antiparallel arrangement leading to fully compensated ferrimagnetism, which possesses broken magnetic inversion symmetry. Such magnetic systems do not produce dipole fields and are extremely stable against external magnetic fields. Therefore, this will improve the performance of spintronic devices. Using this principle, similar band dispersion and compensated magnetic moments were predicted in a C1 b -ordered FeMnAl0.5In0.5 Heusler alloy.
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Affiliation(s)
- Y. J. Zhang
- School of Civil Engineering, Guangzhou University, Guangzhou 510006, People’s Republic of China
| | - Z. H. Liu
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Z. G. Wu
- School of Civil Engineering, Guangzhou University, Guangzhou 510006, People’s Republic of China
| | - X. Q. Ma
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
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Synoradzki K, Ciesielski K, Veremchuk I, Borrmann H, Skokowski P, Szymański D, Grin Y, Kaczorowski D. Thermal and Electronic Transport Properties of the Half-Heusler Phase ScNiSb. Materials (Basel) 2019; 12:ma12101723. [PMID: 31137868 PMCID: PMC6566183 DOI: 10.3390/ma12101723] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 05/24/2019] [Accepted: 05/24/2019] [Indexed: 11/16/2022]
Abstract
Thermoelectric properties of the half-Heusler phase ScNiSb (space group F 4 ¯ 3m) were studied on a polycrystalline single-phase sample obtained by arc-melting and spark-plasma-sintering techniques. Measurements of the thermopower, electrical resistivity, and thermal conductivity were performed in the wide temperature range 2-950 K. The material appeared as a p-type conductor, with a fairly large, positive Seebeck coefficient of about 240 μV K-1 near 450 K. Nevertheless, the measured electrical resistivity values were relatively high (83 μΩm at 350 K), resulting in a rather small magnitude of the power factor (less than 1 × 10-3 W m-1 K-2) in the temperature range examined. Furthermore, the thermal conductivity was high, with a local minimum of about 6 W m-1 K-1 occurring near 600 K. As a result, the dimensionless thermoelectric figure of merit showed a maximum of 0.1 at 810 K. This work suggests that ScNiSb could be a promising base compound for obtaining thermoelectric materials for energy conversion at high temperatures.
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Affiliation(s)
- Karol Synoradzki
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P. O. Box 1410, 50-950 Wrocław, Poland.
| | - Kamil Ciesielski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P. O. Box 1410, 50-950 Wrocław, Poland.
| | - Igor Veremchuk
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Horst Borrmann
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Przemysław Skokowski
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - Damian Szymański
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P. O. Box 1410, 50-950 Wrocław, Poland.
| | - Yuri Grin
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Dariusz Kaczorowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P. O. Box 1410, 50-950 Wrocław, Poland.
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36
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Jirásková Y, Buršík J, Janičkovič D, Životský O. Influence of Preparation Technology on Microstructural and Magnetic Properties of Fe₂MnSi and Fe₂MnAl Heusler Alloys. Materials (Basel) 2019; 12:E710. [PMID: 30823413 PMCID: PMC6427256 DOI: 10.3390/ma12050710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 02/19/2019] [Accepted: 02/21/2019] [Indexed: 11/17/2022]
Abstract
Microstructural and magnetic properties of the X₂YZ, namely Fe₂MnSi and Fe₂MnAl, Heusler alloys have been studied from the viewpoint of technology for their production and for the Z element effect. First, arc melting was applied to produce button-type ingots from which samples in a form of 500 µm thick discs were cut. Second, planar flow casting technology yielded samples in a ribbon-form 2 mm wide and 20 μm thick. The checked area chemical compositions were in agreement with the nominal ones. Nevertheless, the darker square objects and smaller bright objects observed at the wheel side of the Fe₂MnSi ribbon sample yielded higher Mn content at the expense of Fe. The X-ray diffraction patterns of all samples have indicated L2₁ structure with lattice parameters, 0.567 (1) nm for Fe₂MnSi and 0.584 (1) nm for Fe₂MnAl, being within an experimental error independent of production technology. On the other hand, the technology has markedly influenced the microstructure clearly pointing to the larger size of grains and grain boundaries in the disc samples. From the magnetic viewpoint, both alloys are paramagnetic at room temperature without visible influence of their production. On the contrary, the low-temperature behavior of the microscopic hyperfine parameters and the macroscopic magnetic parameters exhibits differences affected by both chemical composition and microstructure.
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Affiliation(s)
- Yvonna Jirásková
- CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno, Czech Republic.
| | - Jiří Buršík
- CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno, Czech Republic.
| | - Dušan Janičkovič
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovakia.
| | - Ondřej Životský
- Department of Physics, VŠB-Technical University of Ostrava, 17 listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.
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Finley J, Lee CH, Huang PY, Liu L. Spin-Orbit Torque Switching in a Nearly Compensated Heusler Ferrimagnet. Adv Mater 2019; 31:e1805361. [PMID: 30412315 DOI: 10.1002/adma.201805361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/10/2018] [Indexed: 06/08/2023]
Abstract
Ferrimagnetic materials combine the advantages of the low magnetic moment of an antiferromagnet and the ease of realizing magnetic reading of a ferromagnet. Recently, it was demonstrated that compensated ferrimagnetic half metals can be realized in Heusler alloys, where high spin polarization, zero magnetic moment, and low magnetic damping can be achieved at the same time. In this work, by studying the spin-orbit torque induced switching in the Heusler alloy Mn2 Ru1- x Ga, it is found that efficient current-induced magnetic switching can be realized in a nearly compensated sample with strong perpendicular anisotropy and large film thickness. This work demonstrates the possibility of employing compensated Heusler alloys for fast, energy-efficient spintronic devices.
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Affiliation(s)
- Joseph Finley
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Chia-Hao Lee
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Pinshane Y Huang
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Luqiao Liu
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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Ahamed Khan RA, Ghomashchi R, Xie Z, Chen L. Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization and Magnetostructural Properties. Materials 2018; 11:E988. [PMID: 29891811 PMCID: PMC6025179 DOI: 10.3390/ma11060988] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 05/26/2018] [Accepted: 06/08/2018] [Indexed: 11/16/2022]
Abstract
An overview of the processing, characterization and magnetostructural properties of ferromagnetic NiMnX (X = group IIIA⁻VA elements) Heusler alloys is presented. This type of alloy is multiferroic—exhibits more than one ferroic property—and is hence multifunctional. Examples of how different synthesis procedures influence the magnetostructural characteristics of these alloys are shown. Significant microstructural factors, such as the crystal structure, atomic ordering, volume of unit cell, grain size and others, which have a bearing on the properties, have been reviewed. An overriding factor is the composition which, through its tuning, affects the martensitic and magnetic transitions, the transformation temperatures, microstructures and, consequently, the magnetostructural effects.
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Affiliation(s)
| | - Reza Ghomashchi
- School of Mechanical Engineering, University of Adelaide, Adelaide 5005, Australia.
| | - Zonghan Xie
- School of Mechanical Engineering, University of Adelaide, Adelaide 5005, Australia.
- School of Engineering, Edith Cowan University, Joondalup WA 6027, Australia.
| | - Lei Chen
- School of Mechanical Engineering, University of Adelaide, Adelaide 5005, Australia.
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Dunzhu G, Wang F, Zhou C, Jiang C. Electric Field Tuning Non-volatile Magnetism in Half-Metallic Alloys Co 2FeAl/Pb(Mg 1/3Nb 2/3)O 3-PbTiO 3 Heterostructure. Nanoscale Res Lett 2018; 13:75. [PMID: 29511911 PMCID: PMC5840109 DOI: 10.1186/s11671-018-2489-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/28/2018] [Indexed: 06/08/2023]
Abstract
We reported the non-volatile electric field-mediated magnetic properties in the half-metallic Heusler alloy Co2FeAl/Pb(Mg1/3Nb2/3)O3-PbTiO3 heterostructure at room temperature. The remanent magnetization with different applied electric field along [100] and [01-1] directions was achieved, which showed the non-volatile remanent magnetization driven by an electric field. The two giant reversible and stable remanent magnetization states were obtained by applying pulsed electric field. This can be attributed to the piezostrain effect originating from the piezoelectric substrate, which can be used for magnetoelectric-based memory devices.
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Affiliation(s)
- Gesang Dunzhu
- Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, 730000 People’s Republic of China
- Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou, 730000 People’s Republic of China
| | - Fenglong Wang
- Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, 730000 People’s Republic of China
- Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou, 730000 People’s Republic of China
| | - Cai Zhou
- Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, 730000 People’s Republic of China
- Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou, 730000 People’s Republic of China
| | - Changjun Jiang
- Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, 730000 People’s Republic of China
- Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou, 730000 People’s Republic of China
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40
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Zhao W, Sun Y, Liu Y, Shi K, Lu H, Song P, Wang L, Han H, Yuan X, Wang C. Negative Thermal Expansion over a Wide Temperature Range in Fe-Doped MnNiGe Composites. Front Chem 2018; 6:15. [PMID: 29468152 PMCID: PMC5808177 DOI: 10.3389/fchem.2018.00015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 01/18/2018] [Indexed: 11/13/2022] Open
Abstract
Fe-doped MnNiGe alloys were successfully synthesized by solid-state reaction. Giant negative thermal expansion (NTE) behaviors with the coefficients of thermal expansion (CTE) of −285.23 × 10−6 K−1 (192–305 K) and −1167.09 × 10−6 K−1 (246–305 K) have been obtained in Mn0.90Fe0.10NiGe and MnNi0.90Fe0.10Ge, respectively. Furthermore, these materials were combined with Cu in order to control the NTE properties. The results indicate that the absolute value of CTE gradually decreases with increasing Cu contents. In Mn0.92Fe0.08NiGe/x%Cu, the CTE gradually changes from −64.92 × 10−6 K−1 (125–274 K) to −4.73 × 10−6 K−1 (173–229 K) with increasing value of x from 15 to 70. The magnetic measurements reveal that the NTE behaviors in this work are strongly correlated with the process of the magnetic phase transition and the introduction of Fe atoms could also change the spiral anti-ferromagnetic (s-AFM) state into ferromagnetic (FM) state at low temperature. Our study launches a new candidate for controlling thermal expansion properties of metal matrix materials which could have potential application in variable temperature environment.
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Affiliation(s)
- Wenjun Zhao
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Ying Sun
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Yufei Liu
- Capital Normal University High School, Beijing, China
| | - Kewen Shi
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Huiqing Lu
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Ping Song
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Lei Wang
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Huimin Han
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Xiuliang Yuan
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
| | - Cong Wang
- Department of Physics, Center for Condensed Matter and Materials Physics, Beihang University, Beijing, China
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Hirohata A, Frost W, Samiepour M, Kim JY. Perpendicular Magnetic Anisotropy in Heusler Alloy Films and Their Magnetoresistive Junctions. Materials (Basel) 2018; 11:E105. [PMID: 29324709 PMCID: PMC5793603 DOI: 10.3390/ma11010105] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 11/24/2022]
Abstract
For the sustainable development of spintronic devices, a half-metallic ferromagnetic film needs to be developed as a spin source with exhibiting 100% spin polarisation at its Fermi level at room temperature. One of the most promising candidates for such a film is a Heusler-alloy film, which has already been proven to achieve the half-metallicity in the bulk region of the film. The Heusler alloys have predominantly cubic crystalline structures with small magnetocrystalline anisotropy. In order to use these alloys in perpendicularly magnetised devices, which are advantageous over in-plane devices due to their scalability, lattice distortion is required by introducing atomic substitution and interfacial lattice mismatch. In this review, recent development in perpendicularly-magnetised Heusler-alloy films is overviewed and their magnetoresistive junctions are discussed. Especially, focus is given to binary Heusler alloys by replacing the second element in the ternary Heusler alloys with the third one, e.g., MnGa and MnGe, and to interfacially-induced anisotropy by attaching oxides and metals with different lattice constants to the Heusler alloys. These alloys can improve the performance of spintronic devices with higher recording capacity.
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Affiliation(s)
- Atsufumi Hirohata
- Department of Electronic Engineering, University of York, York YO10 5DD, UK.
| | - William Frost
- Department of Electronic Engineering, University of York, York YO10 5DD, UK.
| | - Marjan Samiepour
- Department of Electronic Engineering, University of York, York YO10 5DD, UK.
| | - Jun-Young Kim
- Department of Physics, University of York, York YO10 5DD, UK.
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Cugini F, Porcari G, Fabbrici S, Albertini F, Solzi M. Influence of the transition width on the magnetocaloric effect across the magnetostructural transition of Heusler alloys. Philos Trans A Math Phys Eng Sci 2016; 374:20150306. [PMID: 27402934 PMCID: PMC4938065 DOI: 10.1098/rsta.2015.0306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/09/2016] [Indexed: 06/06/2023]
Abstract
We report a complete structural and magneto-thermodynamic characterization of four samples of the Heusler alloy Ni-Co-Mn-Ga-In, characterized by similar compositions, critical temperatures and high inverse magnetocaloric effect across their metamagnetic transformation, but different transition widths. The object of this study is precisely the sharpness of the martensitic transformation, which plays a key role in the effective use of materials and which has its origin in both intrinsic and extrinsic effects. The influence of the transition width on the magnetocaloric properties has been evaluated by exploiting a phenomenological model of the transformation built through geometrical considerations on the entropy versus temperature curves. A clear result is that a large temperature span of the transformation is unfavourable to the magnetocaloric performance of a material, reducing both isothermal entropy change and adiabatic temperature change obtainable in a given magnetic field and increasing the value of the maximum field needed to fully induce the transformation. The model, which is based on standard magnetometric and conventional calorimetric measurements, turns out to be a convenient tool for the determination of the optimum values of transformation temperature span in a trade-off between sheer performance and amplitude of the operating range of a material.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.
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Affiliation(s)
- F Cugini
- Department of Physics and Earth Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - G Porcari
- Department of Physics and Earth Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy
| | - S Fabbrici
- IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - F Albertini
- IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - M Solzi
- Department of Physics and Earth Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy
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Prasanna AA, Ram S. Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni 39+x Mn 50Sn 11-x ( x ⩽ 2) alloys. Sci Technol Adv Mater 2013; 14:015004. [PMID: 27877562 PMCID: PMC5090580 DOI: 10.1088/1468-6996/14/1/015004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 11/06/2012] [Indexed: 06/06/2023]
Abstract
Ni39+x Mn50Sn11-x (x = 0.5, 1.0, 1.5 and 2) alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ∼15 mm diameter and 8 mm width. A single martensite phase with a L10 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% (x = 2), whereas an austenite cubic L21 phase turns up at smaller x ⩽ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips (x ≽ 1.5) with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite-austenite (or reverse) phase transition. A net residual enthalpy change ΔHM↔A = -0.12 J g-1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (-)26% at 10 T is observed together with a large entropy change of 11.8 mJ g-1 K-1, nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The ΔHM↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features.
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Inomata K, Ikeda N, Tezuka N, Goto R, Sugimoto S, Wojcik M, Jedryka E. Highly spin-polarized materials and devices for spintronics ∗. Sci Technol Adv Mater 2008; 9:014101. [PMID: 27877927 PMCID: PMC5099796 DOI: 10.1088/1468-6996/9/1/014101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 03/13/2008] [Accepted: 11/19/2007] [Indexed: 05/09/2023]
Abstract
The performance of spintronics depends on the spin polarization of the current. In this study half-metallic Co-based full-Heusler alloys and a spin filtering device (SFD) using a ferromagnetic barrier have been investigated as highly spin-polarized current sources. The multilayers were prepared by magnetron sputtering in an ultrahigh vacuum and microfabricated using photolithography and Ar ion etching. We investigated two systems of Co-based full-Heusler alloys, Co2Cr1 - x Fe x Al (CCFA(x)) and Co2FeSi1 - x Al x (CFSA(x)) and revealed the structure and magnetic and transport properties. We demonstrated giant tunnel magnetoresistance (TMR) of up to 220% at room temperature and 390% at 5 K for the magnetic tunnel junctions (MTJs) using Co2FeSi0.5Al0.5 (CFSA(0.5)) Heusler alloy electrodes. The 390% TMR corresponds to 0.81 spin polarization for CFSA(0.5) at 5 K. We also investigated the crystalline structure and local structure around Co atoms by x-ray diffraction (XRD) and nuclear magnetic resonance (NMR) analyses, respectively, for CFSA films sputtered on a Cr-buffered MgO (001) substrate followed by post-annealing at various temperatures in an ultrahigh vacuum. The disordered structures in CFSA films were clarified by NMR measurements and the relationship between TMR and the disordered structure was discussed. We clarified that the TMR of the MTJs with CFSA(0.5) electrodes depends on the structure, and is significantly higher for L21 than B2 in the crystalline structure. The second part of this paper is devoted to a SFD using a ferromagnetic barrier. The Co ferrite is investigated as a ferromagnetic barrier because of its high Curie temperature and high resistivity. We demonstrate the strong spin filtering effect through an ultrathin insulating ferrimagnetic Co-ferrite barrier at a low temperature. The barrier was prepared by the surface plasma oxidization of a CoFe2 film deposited on a MgO (001) single crystal substrate, wherein the spinel structure of CoFe2O4 (CFO) and an epitaxial relationship of MgO(001)[100]/CoFe2 (001)]110]/CFO(001)[100] were induced. A SFD consisting of CoFe2 /CFO/Ta on a MgO (001) substrate exhibits the inverse TMR of - 124% at 10 K when the configuration of the magnetizations of CFO and CoFe2 changes from parallel to antiparallel. The inverse TMR suggests the negative spin polarization of CFO, which is consistent with the band structure of CFO obtained by first principle calculation. The - 124% TMR corresponds to the spin filtering efficiency of 77% by the CFO barrier.
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Affiliation(s)
- Koichiro Inomata
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan
| | - Naomichi Ikeda
- Department of Material Science, Graduate School of Engineering, Tohoku University, Aobayama, Sendai 980-8579, Japan
| | - Nobuki Tezuka
- Department of Material Science, Graduate School of Engineering, Tohoku University, Aobayama, Sendai 980-8579, Japan
| | - Ryogo Goto
- Department of Material Science, Graduate School of Engineering, Tohoku University, Aobayama, Sendai 980-8579, Japan
| | - Satoshi Sugimoto
- Department of Material Science, Graduate School of Engineering, Tohoku University, Aobayama, Sendai 980-8579, Japan
| | - Marek Wojcik
- Institute of Physics, Polish Academy of Sciences, Warszawa 02-668, Poland
| | - Eva Jedryka
- Institute of Physics, Polish Academy of Sciences, Warszawa 02-668, Poland
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