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Waschk M, Sarkar A, Barthel J, Voigt J, Schröder S, Zakalek P, Schmitz M, Kirby BJ, Pütter S, Schubert J, Brückel T. Impact of growth kinetics on the interface morphology and magnetization in La 1/3Sr 2/3FeO 3/La 2/3Sr 1/3MnO 3 heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:165801. [PMID: 31899900 DOI: 10.1088/1361-648x/ab678c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The ability to create atomically perfect, epitaxial heterostructures of correlated complex perovskite oxides using state-of-art thin film deposition techniques has generated new physical phenomena at engineered interfaces. Here we report on the impact of growth kinetics on the magnetic structure and exchange coupling at the interface in heterostructures combining layers of antiferromagnetic La1/3Sr2/3FeO3 (LSFO) and ferromagnetic La2/3Sr1/3MnO3 (LSMO) on (0 0 1)-oriented SrTiO3 (STO) substrates. Two growth orders are investigated, (a) LSMO/LSFO/STO(0 0 1) and (b) LSFO/LSMO/STO(0 0 1), where the LSFO layer is grown by molecular beam epitaxy and the LSMO layer by high oxygen pressure sputtering. The interface has been investigated using electron microscopy and polarized neutron reflectometry. Interdiffusion over seven monolayers is observed in LSMO/LSFO (a) with an almost 50% reduction in magnetization at the interface and showing no exchange coupling. However, the exchange bias effect ([Formula: see text] mT at 10 K) could be realized when the interface is atomically sharp, as in LSFO/LSMO (b). Our study therefore reveals that, even for well ordered and lattice-matched structures, the kinetics involved in the growth processes drastically influences the interface quality with a strong correlation to the magnetic properties.
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Affiliation(s)
- M Waschk
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-2) and Peter Grünberg Institut (PGI-4), JARA-FIT, 52425 Jülich, Germany
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Kumar V, Zhou SL, Liu RR, Zhu YM, Liu HJ, Chin YY, Lin HJ, Chen CT, Zhan Q, Chu YH. Antiferromagnetic Interfacial Coupling and Giant Magnetic Hysteresis in La 0.5Ca 0.5MnO 3-SrRuO 3 Superlattices. ACS OMEGA 2018; 3:14266-14273. [PMID: 31458117 PMCID: PMC6645154 DOI: 10.1021/acsomega.8b01851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/12/2018] [Indexed: 06/10/2023]
Abstract
Superlattices are of great importance due to their potential as new materials genome to synthesize new functional materials. Thus, tuning of the ground state of superlattices is crucial to further control their physical properties. In this study, superlattices (SLs) consisting of alternating layers of SrRuO3 (SRO) (5 nm) and La0.5Ca0.5MnO3 (LCMO) (5 nm) are epitaxially grown on SrTiO3 (STO) and LaAlO3 (LAO) substrates with 10-unit-cell periods. A variation in the substrate-induced-strain for this choice of SLs triggers observation of remarkable properties, such as magnetic anisotropy and large magnetic hysteresis. The strain states experienced by LCMO and SRO in these SLs result in strong ferromagnetic interlayer coupling and weak antiferromagnetic interlayer coupling at low temperatures in SLs of LCMO-SRO/STO and a strong antiferromagnetic interlayer coupling in SLs of LCMO-SRO/LAO. Besides, a large magnetic hysteresis resulting from the predominant magnetic anisotropy of SRO together with the strength of magnetic coupling is observed in SLs of LCMO-SRO/LAO along the out-of-plane direction of the LAO substrate. These four different magnetic behaviors along four different directions of substrate orientations are interpreted in terms of preferential orbital occupation and competing magnetic exchange coupling together with magnetic anisotropy. This study demonstrates the subtleties in controlling the strength of magnetic coupling at the interface and stands as a model system to realize fascinating magnetic phenomena in layer-by-layer hetero-epitaxial oxide films.
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Affiliation(s)
- Vandrangi
Suresh Kumar
- School
of Materials Science and Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, 100083 Beijing, China
- School
of Advanced Sciences, Vellore Institute
of Technology, 632014 Vellore, India
| | - Shu-Liang Zhou
- School
of Materials Science and Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, 100083 Beijing, China
| | - Rui-Rui Liu
- School
of Materials Science and Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, 100083 Beijing, China
| | - Yuan-Min Zhu
- School
of Materials Science and Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, 100083 Beijing, China
- Department
of Materials Science and Engineering and Academy for Advanced Interdisciplinary
Studies, Southern University of Science
and Technology of China, No. 1088, Xueyuan Road, 518055 Shenzhen, China
| | - Heng-Jui Liu
- Department
of Materials Science and Engineering, National
Chung Hsing University, 145 Xingda Road, 40227 Taichung, Taiwan
| | - Yi-Ying Chin
- Department
of Physics, National Chung Cheng University, No. 168, Section 1, University Road, Minhsiung Township, 62102 Chiayi, Taiwan
| | - Hong-Ji Lin
- National
Synchrotron Radiation Research Center, 101 Hsin-Ann Road, 30076 Hsinchu, Taiwan
| | - Chien-Te Chen
- National
Synchrotron Radiation Research Center, 101 Hsin-Ann Road, 30076 Hsinchu, Taiwan
| | - Qian Zhan
- School
of Materials Science and Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, 100083 Beijing, China
| | - Ying-Hao Chu
- Department
of Materials Science and Engineering, National
Chiao Tung University, 1001 University Road, 30010 Hsinchu, Taiwan
- Institute
of Physics, Academia Sinica, Section 2, Academia Road, Nangang district, 11529 Taipei, Taiwan
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Sahoo A, Padhan P, Prellier W. Interfacial Antiferromagnetic Coupling and Dual-Exchange Bias in Tetragonal SrRuO 3-PrMnO 3 Superlattices. ACS APPLIED MATERIALS & INTERFACES 2017; 9:36423-36430. [PMID: 28956445 DOI: 10.1021/acsami.7b11930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The functional properties of oxide heterostructures depend on the interfaces accommodating ions, their spins, and structural mismatches. Here, by stabilizing tetragonal symmetry, we achieve the in-plane antiferromagnetic (AFM) ordering and dual-exchange bias in the superlattices consisting of two ferromagnets SrRuO3 (SRO) and PrMnO3 (PMO). The tetragonal symmetry of this superlattice system achieved after the octahedral rotations yield an elongation of the c-axis parameter with Ru-O-Mn bond angle close to 180°, induces an interfacial antiferromagnetic ordering, which is suppressed as the ferromagnetic (FM) ordering in the PMO layer increases. The 0.1 T in-plane cooling field (Hcool) leads to the shift (ca. -0.04 T) of minor hysteresis loop along the negative field axis due to the presence of -0.87 erg/cm2 AFM interfacial exchange coupling energy density (ERu,Mn) at 20 K. The exchange bias field (HEB) switches from negative to positive value with the increase in Hcool. For 5 T Hcool, the HEB is positive, but the ERu,Mn is -1.25 erg/cm2 for n ≤ 8 (n = number of unit cells of PMO) and 1.52 erg/cm2 for n ≥ 8. The HEB and its switching from negative to positive with the increase in Hcool are explained by the interplay of strong antiferromagnetic coupling energy and Zeeman energy at the interfaces. The results demonstrate that the SRO-PMO superlattice could be a model system for the investigation of the interfacial exchange coupling in functional oxides.
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Affiliation(s)
- Antarjami Sahoo
- Department of Physics, Indian Institute of Technology Madras , Chennai 600036, India
| | - Prahallad Padhan
- Department of Physics, Indian Institute of Technology Madras , Chennai 600036, India
| | - Wilfrid Prellier
- Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd du Marechal Juin, F-14050 Caen Cedex, France
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Luo X, Tseng LT, Lee WT, Tan TT, Bao NN, Liu R, Ding J, Li S, Lauter V, Yi JB. Probing the magnetic profile of diluted magnetic semiconductors using polarized neutron reflectivity. Sci Rep 2017; 7:6341. [PMID: 28740239 PMCID: PMC5524716 DOI: 10.1038/s41598-017-06793-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/16/2017] [Indexed: 11/09/2022] Open
Abstract
Room temperature ferromagnetism has been observed in the Cu doped ZnO films deposited under an oxygen partial pressure of 10-3 and 10-5 torr on Pt (200 nm)/Ti (45 nm)/Si (001) substrates using pulsed laser deposition. Due to the deposition at relatively high temperature (873 K), Cu and Ti atoms diffuse to the surface and interface, which significantly affects the magnetic properties. Depth sensitive polarized neutron reflectometry method provides the details of the composition and magnetization profiles and shows that an accumulation of Cu on the surface leads to an increase in the magnetization near the surface. Our results reveal that the presence of the copper at Zn sites induces ferromagnetism at room temperature, confirming intrinsic ferromagnetism.
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Affiliation(s)
- X Luo
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - L T Tseng
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - W T Lee
- Bragg Institute, ANSTO, New Illawarra Road, Lucas Heights, NSW, 2234, Australia
| | - T T Tan
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - N N Bao
- Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore, Singapore
| | - R Liu
- SIMS Facility, Office of the Deputy-Vice Chancellor (Research and Development), Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - J Ding
- Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore, Singapore
| | - S Li
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - V Lauter
- Quantum Condensed Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - J B Yi
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia.
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Wu J, Lauter V, Ambaye H, He X, Božović I. Search for ferromagnetic order in overdoped copper-oxide superconductors. Sci Rep 2017; 7:45896. [PMID: 28378795 PMCID: PMC5381091 DOI: 10.1038/srep45896] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/03/2017] [Indexed: 11/16/2022] Open
Abstract
In copper-oxides that show high-temperature superconductivity (HTS), the critical temperature (Tc) has a dome-shaped doping dependence. The cause of demise of both Tc and superfluid density ns on the overdoped side is a major puzzle. A recent study of transport and diamagnetism in a large number of overdoped La2−xSrxCuO4 (LSCO) films shows that this cannot be accounted for by disorder within the conventional Bardeen-Cooper-Schrieffer theory. This brings to focus an alternative explanation — competition of HTS with ferromagnetic order, fluctuating in superconducting samples and static beyond the superconductor-to-metal transition. Here, we examine this proposal by growing single-crystal LSCO thin films with doping on both sides of the transition by molecular beam epitaxy, and using polarized neutron reflectometry to measure their magnetic moments. In a heavily overdoped, metallic but non-superconducting LSCO (x = 0.35) film, the spin asymmetry of reflectivity shows a very small static magnetic moment (~2 emu/cm3). Less-doped, superconducting LSCO films show no magnetic moment in neutron reflectivity, both above and below Tc. Therefore, the collapse of HTS with overdoping is not caused by competing ferromagnetic order.
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Affiliation(s)
- J Wu
- Brookhaven National Laboratory, Upton, NY 11973, USA
| | - V Lauter
- Quantum Condensed Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - H Ambaye
- Instrument and Source Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - X He
- Applied Physics Department, Yale University, New Haven, CT 06520, USA
| | - I Božović
- Brookhaven National Laboratory, Upton, NY 11973, USA.,Applied Physics Department, Yale University, New Haven, CT 06520, USA
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Zhang J, Zhang H, Zhang X, Guan X, Shen X, Hong D, Zhang H, Liu B, Yu R, Shen B, Sun J. Antiferromagnetic interlayer coupling and thus induced distinct spin texture for the [LaMnO 3/LaCoO 3] 5 superlattices. NANOSCALE 2017; 9:3476-3484. [PMID: 28239702 DOI: 10.1039/c6nr09242j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Artificial engineering of an interfacial spin structure of complex oxides with strongly coupled spin, orbital, charge and lattice degrees of freedom is crucially important for the exploration of novel effects associated with magnetic tunneling, exchange biasing, and spin injecting/manipulating, which are the central issues of spintronics. Here we demonstrate the presence of a distinct interlayer coupling between LaMnO3 (LMO) and LaCoO3 (LCO) and the resulting dramatic effect on the spin structure. We found that the LCO layer in (LMO/LCO)5 superlattices exhibits not only an antiferromagnetic coupling with a neighboring LMO layer but also a long-range magnetic order with substantially reduced magnetization. As suggested by density functional theory calculations, interlayer coupling can induce a spatial oscillation of magnetic moment within the LCO layer, resulting in low magnetization.
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Affiliation(s)
- Jing Zhang
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Hongrui Zhang
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Xuejing Zhang
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Xiangxiang Guan
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Xi Shen
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Deshun Hong
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Hui Zhang
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Banggui Liu
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Richeng Yu
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Jirong Sun
- Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
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7
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Wahler M, Homonnay N, Richter T, Müller A, Eisenschmidt C, Fuhrmann B, Schmidt G. Inverse spin Hall effect in a complex ferromagnetic oxide heterostructure. Sci Rep 2016; 6:28727. [PMID: 27346793 PMCID: PMC4921828 DOI: 10.1038/srep28727] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 06/08/2016] [Indexed: 11/09/2022] Open
Abstract
We present spin pumping and inverse spin Hall effect (ISHE) in an epitaxial complex oxide heterostructure. Ferromagnetic La0.7Sr0.3MnO3 (LSMO) is used as a source of spin pumping while the spin sink exhibiting the ISHE consists of SrRuO3 (SRO). SRO is a ferromagnetic oxide with metallic conductivity, however, with a Curie temperature (TC) of 155 K, thus well below room temperature. This choice allows to perform the experiment above and below TC of the SRO and to demonstrate that SRO not only shows an ISHE of a magnitude comparable to Pt (though with opposite sign) in its non magnetic state but also exhibits a finite ISHE even 50 K below TC.
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Affiliation(s)
- Martin Wahler
- Institut für Physik, Martin-Luther University Halle-Wittenberg, Halle, 06120, Germany
| | - Nico Homonnay
- Institut für Physik, Martin-Luther University Halle-Wittenberg, Halle, 06120, Germany
| | - Tim Richter
- Institut für Physik, Martin-Luther University Halle-Wittenberg, Halle, 06120, Germany
| | - Alexander Müller
- Institut für Physik, Martin-Luther University Halle-Wittenberg, Halle, 06120, Germany
| | | | - Bodo Fuhrmann
- Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther University Halle-Wittenberg, Nanotechnikum Weinberg, Halle, 06120, Germany
| | - Georg Schmidt
- Institut für Physik, Martin-Luther University Halle-Wittenberg, Halle, 06120, Germany
- Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther University Halle-Wittenberg, Nanotechnikum Weinberg, Halle, 06120, Germany
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8
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Liu Y, Ke X. Interfacial magnetism in complex oxide heterostructures probed by neutrons and x-rays. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:373003. [PMID: 26328474 DOI: 10.1088/0953-8984/27/37/373003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Magnetic complex-oxide heterostructures are of keen interest because a wealth of phenomena at the interface of dissimilar materials can give rise to fundamentally new physics and potentially valuable functionalities. Altered magnetization, novel magnetic coupling and emergent interfacial magnetism at the epitaxial layered-oxide interfaces are under intensive investigation, which shapes our understanding on how to utilize those materials, particularly for spintronics. Neutron and x-ray based techniques have played a decisive role in characterizing interfacial magnetic structures and clarifying the underlying physics in this rapidly developing field. Here we review some recent experimental results, with an emphasis on those studied via polarized neutron reflectometery and polarized x-ray absorption spectroscopy. We conclude with some perspectives.
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Affiliation(s)
- Yaohua Liu
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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