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Chi X, Guo R, Xiong J, Ren L, Peng X, Tay BK, Chen J. Enhanced Tunneling Magnetoresistance Effect via Ferroelectric Control of Interface Electronic/Magnetic Reconstructions. ACS APPLIED MATERIALS & INTERFACES 2021; 13:56638-56644. [PMID: 34786928 DOI: 10.1021/acsami.1c15836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Magnetic tunnel junctions (MTJs) with tunable tunneling magnetoresistances (TMR) have already been proven to have great potential for spintronics. Especially, when ferroelectric materials are used as insulating barriers, more novel functions of MTJs can be realized due to interface magnetoelectric coupling. Here, we demonstrate a very large ferroelectric modulation of TMR (as high as 570% in low-resistance state) in the ferroelectric/magnetic La0.5Sr0.5MnO3/BaTiO3 (LSMO/BTO) junctions and find robust interfacial electronic and magnetic reconstructions via ferroelectric polarization switching. Through electrical, magnetic, and optical measurements combined with X-ray absorption and magnetic circular dichroism, we reveal that the interfacial electronic and magnetic (ferromagnetic/antiferromagnetic phase transition) reconstructions originate from strong electromagnetic coupling between BTO and LSMO at the interface and are driven by the modulation of hole/electron doping at the interface of LSMO/BTO through ferroelectric polarization switching. As a result, the ferroelectrically controlled interface barrier height and width and spin filter effect enable a giant electrical modulation of TMR. Our results shed new light on the intrinsic mechanisms governing magnetoelectric coupling and offering a new route to enhance magnetoelectric coupling for spin control in spintronic devices.
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Affiliation(s)
- Xiao Chi
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China
| | - Rui Guo
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
- Centre for Micro- and Nano-Electronics (CMNE), School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- UMI 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Research Techno Plaza, 50 Nanyang Drive, 637553 Singapore
| | - Juxia Xiong
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, P.R. China
| | - Lizhu Ren
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore
| | - Xinwen Peng
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China
| | - Beng Kang Tay
- Centre for Micro- and Nano-Electronics (CMNE), School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- UMI 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Research Techno Plaza, 50 Nanyang Drive, 637553 Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
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Jin C, Li X, Han W, Liu Q, Hu S, Ji Y, Xu Z, Hu S, Ye M, Gu M, Zhu Y, Chen L. Ferroelectricity and Ferromagnetism Achieved via Adjusting Dimensionality in BiFeO 3/BiMnO 3 Superlattices. ACS APPLIED MATERIALS & INTERFACES 2021; 13:41315-41322. [PMID: 34410105 DOI: 10.1021/acsami.1c11120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Integrating characteristics of materials through constructing artificial superlattices (SLs) has raised extensive attention in multifunctional materials. Here, we report the synthesis of BiFeO3/BiMnO3 SLs with considerable ferroelectric polarizations and tunable magnetic moments. The polarization of BiFeO3/BiMnO3 SLs presents a decent value of 12 μC/cm2, even as the dimensionality of BiFeO3 layers per period is reduced to about five-unit cells when keeping the BiMnO3 layers same. Moreover, it is found that the tunable magnetic moments of SLs are linked intimately to the dimensionality of BiFeO3 layers. Our simulations demonstrate that the superexchange interaction of Fe-O-Mn tends to be antiferromagnetic (AFM) with a lower magnetic domain formation energy rather than ferromagnetic (FM). Therefore, as the dimensionality of BiFeO3 per period is reduced, the AFM superexchange interaction between BiFeO3 and BiMnO3 in the SLs becomes weak, promoting a robust magnetization. This interlayer modulation effect in SLs presents an alluring way to accurately control the multiple order parameters in a multiferroic oxide system.
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Affiliation(s)
- Cai Jin
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- School of Physics, Harbin Institute of Technology, Harbin 150081, China
| | - Xiaowen Li
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenqiao Han
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qi Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Sixia Hu
- Materials Characterization and Preparation Center, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yanjiang Ji
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zedong Xu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Songbai Hu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mao Ye
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Meng Gu
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuanmin Zhu
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Lang Chen
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Materials Characterization and Preparation Center, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Abstract
Electric field control of magnetism is an extremely exciting area of research, from both a fundamental science and an applications perspective and has the potential to revolutionize the world of computing. To realize this will require numerous further innovations, both in the fundamental science arena as well as translating these scientific discoveries into real applications. Thus, this article will attempt to bridge the gap between condensed matter physics and the actual manifestations of the physical concepts into applications. We have attempted to paint a broad-stroke picture of the field, from the macroscale all the way down to the fundamentals of spin–orbit coupling that is a key enabler of the physics discussed. We hope it will help spur more translational research within the broad materials physics community. Needless to say, this article is written on behalf of a large number of colleagues, collaborators and researchers in the field of complex oxides as well as current and former students and postdocs who continue to pursue cutting-edge research in this field.
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Affiliation(s)
- Ramamoorthy Ramesh
- Department of Physics, University of California, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Sasikanth Manipatruni
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kepler Computing, Portland, OR 97229, USA
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Liu C, Liu Y, Zhang B, Sun CJ, Lan D, Chen P, Wu X, Yang P, Yu X, Charlton T, Fitzsimmons MR, Ding J, Chen J, Chow GM. Ferroelectric Self-Polarization Controlled Magnetic Stratification and Magnetic Coupling in Ultrathin La 0.67Sr 0.33MnO 3 Films. ACS APPLIED MATERIALS & INTERFACES 2021; 13:30137-30145. [PMID: 34137601 DOI: 10.1021/acsami.1c02300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Multiferroic oxide heterostructures consisting of ferromagnetic and ferroelectric components hold the promise for nonvolatile magnetic control via ferroelectric polarization, advantageous for the low-dissipation spintronics. Modern understanding of the magnetoelectric coupling in these systems involves structural, orbital, and magnetic reconstructions at interfaces. Previous works have long proposed polarization-dependent interfacial magnetic structures; however, direct evidence is still missing, which requires advanced characterization tools with near-atomic-scale spatial resolutions. Here, extensive polarized neutron reflectometry (PNR) studies have determined the magnetic depth profiles of PbZr0.2Ti0.8O3/La0.67Sr0.33MnO3 (PZT/LSMO) bilayers with opposite self-polarizations. When the LSMO is 2-3 nm thick, the bilayers show two magnetic transitions on cooling. However, temperature-dependent magnetization is different below the lower-temperature transition for opposite polarizations. PNR finds that the LSMO splits into two magnetic sublayers, but the inter-sublayer magnetic couplings are of opposite signs for the two polarizations. Near-edge X-ray absorption spectroscopy further shows contrasts in both the Mn valences and the Mn-O bond anisotropy between the two polarizations. This work completes the puzzle for the magnetoelectric coupling model at the PZT/LSMO interface, showing a synergic interplay among multiple degrees of freedom toward emergent functionalities at complex oxide interfaces.
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Affiliation(s)
- Chao Liu
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yaohua Liu
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Bangmin Zhang
- School of Physics, Sun Yat-Sen University, Guangzhou510275 Guangdong, China
| | - Cheng-Jun Sun
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Da Lan
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Pingfan Chen
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Xiaohan Wu
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore
| | - Timothy Charlton
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michael R Fitzsimmons
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jun Ding
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Jingsheng Chen
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Gan Moog Chow
- Department of Materials Science & Engineering, National University of Singapore, Singapore 117575, Singapore
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5
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Jin C, Geng W, Wang L, Han W, Zheng D, Hu S, Ye M, Xu Z, Ji Y, Zhao J, Chen Z, Wang G, Tang Y, Zhu Y, Ma X, Chen L. Tuning ferroelectricity and ferromagnetism in BiFeO 3/BiMnO 3 superlattices. NANOSCALE 2020; 12:9810-9816. [PMID: 32329477 DOI: 10.1039/c9nr09670a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multiferroic materials with multifunctional characteristics play a critical role in the field of microelectronics. In a perovskite oxide, ferroelectric polarization and ferromagnetism usually cannot coexist in a single-phase material at the same time. In this work, we design a superlattice structure composed of alternating BiFeO3 and BiMnO3 layers and illustrate how tuning the supercell size of epitaxial BiFeO3/BiMnO3 superlattices facilitates ferroelectric polarization while maintaining relatively strong ferromagnetism. A comprehensive investigation reveals that the enhanced ferroelectric polarization of BiMnO3 layers originates from the induction effect induced by a strong polarization field generated by the adjacent ferroelectric BiFeO3 layers. For the magnetic behavior, we consider the existence of interfacial antiferromagnetic superexchange interaction of Fe-O-Mn between BiFeO3 and BiMnO3 layers in our superlattices. This modulation effect of artificial superlattices provides a platform to accurately control the multiple order parameters in a multiferroic oxide system.
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Affiliation(s)
- Cai Jin
- School of Physics, Harbin Institute of Technology, Harbin 150081, China
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Wang L, Feng C, Li Y, Meng F, Wang S, Yao M, Xu X, Yang F, Li B, Yu G. Switchable Magnetic Anisotropy of Ferromagnets by Dual-Ion-Manipulated Orbital Engineering. ACS APPLIED MATERIALS & INTERFACES 2019; 11:32475-32480. [PMID: 31365225 DOI: 10.1021/acsami.9b09342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Tailoring magnetic anisotropy of ferromagnetic films is a critical issue in constructing energy-efficient and high-density magnetic memory devices. Presently, the effective tunability was focused on a single-ion-manipulated electronic structure evolution. Here, we reported a new strategy of dual-ion-tuned orbital structure and magnetic anisotropy of ferromagnetic films. N-doped Fe/MgO bilayer films were deposited on shape memory alloy substrates which can generate a significant lattice strain on the films. Before the N ions participate into the manipulation, the Fe/MgO film shows an in-plane magnetic anisotropy, which may be due to excessive Fe-O orbital hybridization. Interestingly, the N and O ions synergistically manipulate electronic coordination of the Fe layer, which can be further modified by the lattice strain through a charge transfer among N-Fe-O. Under such effect, the magnetic anisotropy of the film is switchable from in-plane to perpendicular magnetic anisotropy (PMA). The X-ray line dichroism (XLD) characterization reveals that the anisotropy regulation is related to Fe 3d orbital evolution: N-Fe orbital hybridization promotes the Fe dz2 orbital occupation effectively, which is beneficial in increasing PMA by strengthening Fe-O orbital hybridization along the out-of-plane direction. However, the compressive strain induces a N-Fe-O charge transfer and reduces the Fe dz2 electronic occupation, which weakens the PMA of films. These findings provide a new dimensionality for regulating orbital performance of ferromagnetic materials and developing strain-assisted memory devices.
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Affiliation(s)
| | | | | | | | | | | | | | - Feng Yang
- State Key Laboratory of Heavy Oil Processing , China University of Petroleum-Beijing , Beijing 102249 , China
| | - Baohe Li
- Department of Physics, School of Sciences , Beijing Technology and Business University , Beijing 100048 , China
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7
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Cui D, Gu M, Li C, Duan H, Yan W, Wang P, Li A, Wu D. Interface electron transfer and thickness dependent transport characteristics of La 0.7Sr 0.3VO 3 thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:245002. [PMID: 30865938 DOI: 10.1088/1361-648x/ab0f68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
La0.7Sr0.3VO3 (LSVO) thin films, 5-30 unit cells (u.c.) in thickness, have been epitaxially deposited on (0 0 1) SrTiO3 (STO) single crystal substrates. Although LSVO is metallic in bulk, insulating behavior is observed, from 2 to 390 K, in LSVO films less than 9 u.c. in thickness, while thicker films show a metal-insulator transition with the critical temperature increasing with the decrease of film thickness. X-ray absorption spectra reveal a charge transfer across the LSVO/STO interface for a continuous increase of V valence in LSVO, as well as a decrease of Ti valence in interfacial STO, with the LSVO film thickness increases. The transport characteristics are discussed in terms of enhanced electron localization due to the reduction of film thickness and V 3d band filling induced by the charge transfer.
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Affiliation(s)
- Dapeng Cui
- National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering and Jiangsu Key Laboratory for Artificial Functional Materials, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
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8
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Molinari A, Hahn H, Kruk R. Voltage-Control of Magnetism in All-Solid-State and Solid/Liquid Magnetoelectric Composites. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806662. [PMID: 30785649 DOI: 10.1002/adma.201806662] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/20/2018] [Indexed: 06/09/2023]
Abstract
The control of magnetism by means of low-power electric fields, rather than dissipative flowing currents, has the potential to revolutionize conventional methods of data storage and processing, sensing, and actuation. A promising strategy relies on the utilization of magnetoelectric composites to finely tune the interplay between electric and magnetic degrees of freedom at the interface of two functional materials. Albeit early works predominantly focused on the magnetoelectric coupling at solid/solid interfaces; however, recently there has been an increased interest related to the opportunities offered by liquid-gating techniques. Here, a comparative overview on voltage control of magnetism in all-solid-state and solid/liquid composites is presented within the context of the principal coupling mediators, i.e., strain, charge carrier doping, and ionic intercalation. Further, an exhaustive and critical discussion is carried out, concerning the suitability of using the common definition of coupling coefficient α C = Δ M Δ E to compare the strength of the interaction between electricity and magnetism among different magnetoelectric systems.
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Affiliation(s)
- Alan Molinari
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Horst Hahn
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- KIT-TUD-Joint Research Laboratory Nanomaterials, Technical University Darmstadt, Jovanka-Bontschits-Strasse 2, 64287, Darmstadt, Germany
| | - Robert Kruk
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
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Wang H, Chi X, Liu Z, Yoong H, Tao L, Xiao J, Guo R, Wang J, Dong Z, Yang P, Sun CJ, Li C, Yan X, Wang J, Chow GM, Tsymbal EY, Tian H, Chen J. Atomic-Scale Control of Magnetism at the Titanite-Manganite Interfaces. NANO LETTERS 2019; 19:3057-3065. [PMID: 30964306 DOI: 10.1021/acs.nanolett.9b00441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Complex oxide thin-film heterostructures often exhibit magnetic properties different from those known for bulk constituents. This is due to the altered local structural and electronic environment at the interfaces, which affects the exchange coupling and magnetic ordering. The emergent magnetism at oxide interfaces can be controlled by ferroelectric polarization and has a strong effect on spin-dependent transport properties of oxide heterostructures, including magnetic and ferroelectric tunnel junctions. Here, using prototype La2/3Sr1/3MnO3/BaTiO3 heterostructures, we demonstrate that ferroelectric polarization of BaTiO3 controls the orbital hybridization and magnetism at heterointerfaces. We observe changes in the enhanced orbital occupancy and significant charge redistribution across the heterointerfaces, affecting the spin and orbital magnetic moments of the interfacial Mn and Ti atoms. Importantly, we find that the exchange coupling between Mn and Ti atoms across the interface is tuned by ferroelectric polarization from ferromagnetic to antiferromagnetic. Our findings provide a viable route to electrically control complex magnetic configurations at artificial multiferroic interfaces, taking a step toward low-power spintronics.
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Affiliation(s)
- Han Wang
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Xiao Chi
- Department of Physics , National University of Singapore , 2 Science Drive 3 , 117542 Singapore
- Singapore Synchrotron Light Source (SSLS) , National University of Singapore , 117603 Singapore
| | - ZhongRan Liu
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - HerngYau Yoong
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - LingLing Tao
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience , University of Nebraska , Lincoln , Nebraska 68588-0299 , United States
| | - JuanXiu Xiao
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Rui Guo
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - JingXian Wang
- School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore
| | - ZhiLi Dong
- School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS) , National University of Singapore , 117603 Singapore
| | - Cheng-Jun Sun
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - ChangJian Li
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - XiaoBing Yan
- College of Electron and Information Engineering , Hebei University , Baoding 071002 , China
| | - John Wang
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Gan Moog Chow
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience , University of Nebraska , Lincoln , Nebraska 68588-0299 , United States
| | - He Tian
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Jingsheng Chen
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
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10
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Yi D, Yu P, Chen YC, Lee HH, He Q, Chu YH, Ramesh R. Tailoring Magnetoelectric Coupling in BiFeO 3 /La 0.7 Sr 0.3 MnO 3 Heterostructure through the Interface Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806335. [PMID: 30663174 DOI: 10.1002/adma.201806335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/15/2018] [Indexed: 06/09/2023]
Abstract
Electric field control of magnetism ultimately opens up the possibility of reducing energy consumption of memory and logic devices. Electric control of magnetization and exchange bias are demonstrated in all-oxide heterostructures of BiFeO3 (BFO) and La0.7 Sr0.3 MnO3 (LSMO). However, the role of the polar heterointerface on magnetoelectric (ME) coupling is not fully explored. Here, the ME coupling in BFO/LSMO heterostructures with two types of interfaces, achieved by exploiting the interface engineering at the atomic scale, is investigated. It is shown that both magnetization and exchange bias are reversibly controlled by switching the ferroelectric polarization of BFO. Intriguingly, distinctly different modulation behaviors that depend on the interfacial atomic sequence are observed. These results provide new insights into the underlying physics of ME coupling in the model system. This study highlights that designing interface at the atomic scale is of general importance for functional spintronic devices.
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Affiliation(s)
- Di Yi
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Pu Yu
- State Key Laboratory for Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Hsin-Hua Lee
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Qing He
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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11
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Paudel B, Vasiliev I, Hammouri M, Karpov D, Chen A, Lauter V, Fohtung E. Strain vs. charge mediated magnetoelectric coupling across the magnetic oxide/ferroelectric interfaces. RSC Adv 2019; 9:13033-13041. [PMID: 35520794 PMCID: PMC9063773 DOI: 10.1039/c9ra01503e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Accepted: 04/22/2019] [Indexed: 11/21/2022] Open
Abstract
We utilize polarized neutron reflectometry (PNR) in consort with ab initio based density functional theory (DFT) calculations to study magnetoelectric coupling at the interface of a ferroelectric PbZr0.2Ti0.8O3 (PZT) and magnetic La0.67Sr0.33MnO3 (LSMO) heterostructure grown on a Nb-doped SrTiO3 (001) substrate. Functional device working conditions are mimicked by gating the heterostructure with a Pt top electrode to apply an external electric field, which alters the magnitude and switches the direction of the ferroelectric (FE) polarization, across the PZT layer. PNR results show that the gated PZT/LSMO exhibits interfacial magnetic phase modulation attributed to ferromagnetic (FM) to A-antiferromagnetic (A-AF) phase transitions resulting from hole accumulation. When the net FE polarization points towards the interface (positive), the interface doesn't undergo a magnetic phase transition and retains its global FM ordered state. In addition to changes in the interfacial magnetic ordering, the global magnetization of LSMO increases while switching the polarization from positive to negative and decreases vice versa. DFT calculations indicate that this enhanced magnetization also correlates with an out of plane tensile strain, whereas the suppressed magnetization for positive polarization is attributed to out of plane compressive strain. These calculations also show the coexistence of FM and A-AF phases at zero out of plane strain. Charge modulations throughout the LSMO layer appear to be unaffected by strain, suggesting that these charge mediated effects do not significantly change the global magnetization. Our PNR results and DFT calculations are in consort to verify that the interfacial magnetic modulations are due to co-action of strain and charge mediated effects with the strain and charge effects dominant at different length scale. We utilize polarized neutron reflectometry in consort with ab initio based density functional theory calculations to study interface magnetoelectric coupling across a ferroelectric PbZr0.2Ti0.8O3 and magnetic La0.67Sr0.33MnO3 heterostructure.![]()
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Affiliation(s)
- Binod Paudel
- Department of Physics
- New Mexico State University
- Las Cruces
- USA
- Center for Integrated Nanotechnologies (CINT)
| | - Igor Vasiliev
- Department of Physics
- New Mexico State University
- Las Cruces
- USA
| | | | - Dmitry Karpov
- Swiss Light Source
- Paul Scherrer Institute
- Switzerland
| | - Aiping Chen
- Center for Integrated Nanotechnologies (CINT)
- Los Alamos National Laboratory
- Los Alamos
- USA
| | - Valeria Lauter
- Neutron Scattering Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Edwin Fohtung
- Department of Physics
- New Mexico State University
- Las Cruces
- USA
- Los Alamos National Laboratory
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12
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Xu Z, Hu S, Wu R, Wang JO, Wu T, Chen L. Strain-Enhanced Charge Transfer and Magnetism at a Manganite/Nickelate Interface. ACS APPLIED MATERIALS & INTERFACES 2018; 10:30803-30810. [PMID: 30130085 DOI: 10.1021/acsami.8b06949] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The strain effect on charge transfer in correlated oxide La0.8Sr0.2MnO3/NdNiO3 (LSMO/NNO) heterostructures is investigated. This is achieved by carefully tailoring the strain on the two layers using various substrates. In contrast to bare LSMO films, the strain dependence of the enhanced magnetic moment of the LSMO/NNO bilayers strongly suggests that the charge transfer can be controlled via strain engineering in complex oxide heterostructures. Furthermore, our study also reveals that the coercive field, exchange bias, and conductivity are dramatically affected by the strain-modulated charge transfer in LSMO/NNO heterostructures. Our work thus points out a new path to control electronic states in oxide heterostructures to advance the use of interfaces in oxide-based electronics.
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Affiliation(s)
- Zedong Xu
- Department of Physics , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
| | - Songbai Hu
- Department of Physics , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
| | - Rui Wu
- Laboratory of Synchrotron Radiation , Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100039 , China
| | - Jia-Ou Wang
- Laboratory of Synchrotron Radiation , Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100039 , China
| | - Tom Wu
- School of Materials Science and Engineering , UNSW Australia , Sydney , New South Wales 2052 , Australia
| | - Lang Chen
- Department of Physics , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
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Yi D, Lu N, Chen X, Shen S, Yu P. Engineering magnetism at functional oxides interfaces: manganites and beyond. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:443004. [PMID: 28745614 DOI: 10.1088/1361-648x/aa824d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The family of transition metal oxides (TMOs) is a large class of magnetic materials that has been intensively studied due to the rich physics involved as well as the promising potential applications in next generation electronic devices. In TMOs, the spin, charge, orbital and lattice are strongly coupled, and significant advances have been achieved to engineer the magnetism by different routes that manipulate these degrees of freedom. The family of manganites is a model system of strongly correlated magnetic TMOs. In this review, using manganites thin films and the heterostructures in conjunction with other TMOs as model systems, we review the recent progress of engineering magnetism in TMOs. We first discuss the role of the lattice that includes the epitaxial strain and the interface structural coupling. Then we look into the role of charge, focusing on the interface charge modulation. Having demonstrated the static effects, we continue to review the research on dynamical control of magnetism by electric field. Next, we review recent advances in heterostructures comprised of high T c cuprate superconductors and manganites. Following that, we discuss the emergent magnetic phenomena at interfaces between 3d TMOs and 5d TMOs with strong spin-orbit coupling. Finally, we provide our outlook for prospective future directions.
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Affiliation(s)
- Di Yi
- Geballe Laboratory for Advanced Materials and Applied Physics Department, Stanford University, Stanford, CA 94305, United States of America
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14
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Hong X. Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:103003. [PMID: 26881391 DOI: 10.1088/0953-8984/28/10/103003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling.
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Affiliation(s)
- Xia Hong
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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15
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Trassin M. Low energy consumption spintronics using multiferroic heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:033001. [PMID: 26703387 DOI: 10.1088/0953-8984/28/3/033001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We review the recent progress in the field of multiferroic magnetoelectric heterostructures. The lack of single phase multiferroic candidates exhibiting simultaneously strong and coupled magnetic and ferroelectric orders led to an increased effort into the development of artificial multiferroic heterostructures in which these orders are combined by assembling different materials. The magnetoelectric coupling emerging from the created interface between the ferroelectric and ferromagnetic layers can result in electrically tunable magnetic transition temperature, magnetic anisotropy or magnetization reversal. The full potential of low energy consumption magnetic based devices for spintronics lies in our understanding of the magnetoelectric coupling at the scale of the ferroic domains. Although the thin film synthesis progresses resulted into the complete control of ferroic domain ordering using epitaxial strain, the local observation of magnetoelectric coupling remains challenging. The ability to imprint ferroelectric domains into ferromagnets and to manipulate those solely using electric fields suggests new technological advances for spintronics such as magnetoelectric memories or memristors.
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Affiliation(s)
- Morgan Trassin
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich
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16
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Hu JM, Chen LQ, Nan CW. Multiferroic Heterostructures Integrating Ferroelectric and Magnetic Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:15-39. [PMID: 26551616 DOI: 10.1002/adma.201502824] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/18/2015] [Indexed: 06/05/2023]
Abstract
Multiferroic heterostructures can be synthesized by integrating monolithic ferroelectric and magnetic materials, with interfacial coupling between electric polarization and magnetization, through the exchange of elastic, electric, and magnetic energy. Although the nature of the interfaces remains to be unraveled, such cross coupling can be utilized to manipulate the magnetization (or polarization) with an electric (or magnetic) field, known as a converse (or direct) magnetoelectric effect. It can be exploited to significantly improve the performance of or/and add new functionalities to many existing or emerging devices such as memory devices, tunable microwave devices, sensors, etc. The exciting technological potential, along with the rich physical phenomena at the interface, has sparked intensive research on multiferroic heterostructures for more than a decade. Here, we summarize the most recent progresses in the fundamental principles and potential applications of the interface-based magnetoelectric effect in multiferroic heterostructures, and present our perspectives on some key issues that require further study in order to realize their practical device applications.
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Affiliation(s)
- Jia-Mian Hu
- State Key Laboratory of New Ceramics and Fine Processing and School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Long-Qing Chen
- State Key Laboratory of New Ceramics and Fine Processing and School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Ce-Wen Nan
- State Key Laboratory of New Ceramics and Fine Processing and School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
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17
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Taniyama T. Electric-field control of magnetism via strain transfer across ferromagnetic/ferroelectric interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:504001. [PMID: 26613163 DOI: 10.1088/0953-8984/27/50/504001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
By taking advantage of the coupling between magnetism and ferroelectricity, ferromagnetic (FM)/ferroelectric (FE) multiferroic interfaces play a pivotal role in manipulating magnetism by electric fields. Integrating the multiferroic heterostructures into spintronic devices significantly reduces energy dissipation from Joule heating because only an electric field is required to switch the magnetic element. New concepts of storage and processing of information thus can be envisioned when the electric-field control of magnetism is a viable alternative to the traditional current based means of controlling magnetism. This article reviews some salient aspects of the electric-field effects on magnetism, providing a short overview of the mechanisms of magneto-electric (ME) coupling at the FM/FE interfaces. A particular emphasis is placed on the ME effect via interfacial magneto-elastic coupling arising from strain transfer from the FE to FM layer. Recent results that demonstrate the electric-field control of magnetic anisotropy, magnetic order, magnetic domain wall motion, and etc are described. Obstacles that need to be overcome are also discussed for making this a reality for future device applications.
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Affiliation(s)
- Tomoyasu Taniyama
- Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503, Japan
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18
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Gianfrancesco AG, Tselev A, Baddorf AP, Kalinin SV, Vasudevan RK. The Ehrlich-Schwoebel barrier on an oxide surface: a combined Monte-Carlo and in situ scanning tunneling microscopy approach. NANOTECHNOLOGY 2015; 26:455705. [PMID: 26489518 DOI: 10.1088/0957-4484/26/45/455705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The controlled growth of epitaxial films of complex oxides requires an atomistic understanding of key parameters determining final film morphology, such as termination dependence on adatom diffusion, and height of the Ehrlich-Schwoebel (ES) barrier. Here, through an in situ scanning tunneling microscopy study of mixed-terminated La5/8Ca3/8MnO3 (LCMO) films, we image adatoms and observe pile-up at island edges. Image analysis allows determination of the population of adatoms at the edge of islands and fractions on A-site and B-site terminations. A simple Monte-Carlo model, simulating the random walk of adatoms on a sinusoidal potential landscape using Boltzmann statistics is used to reproduce the experimental data, and provides an estimate of the ES barrier as ∼0.18 ± 0.04 eV at T = 1023 K, similar to those of metal adatoms on metallic surfaces. These studies highlight the utility of in situ imaging, in combination with basic Monte-Carlo methods, in elucidating the factors which control the final film growth in complex oxides.
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Affiliation(s)
- Anthony G Gianfrancesco
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831, USA. ORNL Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge TN 37831, USA. UT/ORNL Bredesen Center, University of Tennessee, Knoxville, TN, USA
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19
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Cui B, Song C, Mao H, Wu H, Li F, Peng J, Wang G, Zeng F, Pan F. Magnetoelectric Coupling Induced by Interfacial Orbital Reconstruction. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:6651-6. [PMID: 26413768 DOI: 10.1002/adma.201503115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 07/28/2015] [Indexed: 05/28/2023]
Abstract
Reversible orbital reconstruction driven by ferroelectric polarization modulates the magnetic performance of model ferroelectric/ferromagnetic heterostructures without onerous limitations. Mn-d(x2-y2) orbital occupancy and related interfacial exotic magnetic states are enhanced and weakened by negative and positive electric fields, respectively, filling the missing member-orbital in the mechanism of magnetoelectric coupling and advancing the application of orbitals to microelectronics.
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Affiliation(s)
- Bin Cui
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Cheng Song
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Haijun Mao
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Huaqiang Wu
- Institute of Microelectronics, Tsinghua University, Beijing, 100084, China
| | - Fan Li
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Jingjing Peng
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Guangyue Wang
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Fei Zeng
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Feng Pan
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
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20
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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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21
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Wang Y, Zhou X, Song C, Yan Y, Zhou S, Wang G, Chen C, Zeng F, Pan F. Electrical control of the exchange spring in antiferromagnetic metals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:3196-3201. [PMID: 25865870 DOI: 10.1002/adma.201405811] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/15/2015] [Indexed: 06/04/2023]
Abstract
Electrical control of the exchange spring in antiferromagnetic metals is obtained in [Co/Pt]/IrMn Hall devices by using an ionic liquid, where the exchange spring could transfer the "force" and enable a deeper modulation depth in the IrMn. This work provides a new approach toward electrical modulation of the spin structures in metallic antiferromagnets, which should be significant in advancing the development of low-power-consumption antiferromagnet (AFM) spintronics.
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Affiliation(s)
- Yuyan Wang
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Xiang Zhou
- Shanghai Key Laboratory of Special Artificial Microstructure and Pohl Institute of Solid State, Physics and School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Cheng Song
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Yinuo Yan
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Shiming Zhou
- Shanghai Key Laboratory of Special Artificial Microstructure and Pohl Institute of Solid State, Physics and School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Guangyue Wang
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Chao Chen
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Fei Zeng
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Feng Pan
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
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22
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Tselev A, Vasudevan RK, Gianfrancesco AG, Qiao L, Ganesh P, Meyer TL, Lee HN, Biegalski MD, Baddorf AP, Kalinin SV. Surface Control of Epitaxial Manganite Films via Oxygen Pressure. ACS NANO 2015; 9:4316-4327. [PMID: 25758864 DOI: 10.1021/acsnano.5b00743] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The trend to reduce device dimensions demands increasing attention to atomic-scale details of structure of thin films as well as to pathways to control it. This is of special importance in the systems with multiple competing interactions. We have used in situ scanning tunneling microscopy to image surfaces of La5/8Ca3/8MnO3 films grown by pulsed laser deposition. The atomically resolved imaging was combined with in situ angle-resolved X-ray photoelectron spectroscopy. We find a strong effect of the background oxygen pressure during deposition on structural and chemical features of the film surface. Deposition at 50 mTorr of O2 leads to mixed-terminated film surfaces, with B-site (MnO2) termination being structurally imperfect at the atomic scale. A relatively small reduction of the oxygen pressure to 20 mTorr results in a dramatic change of the surface structure leading to a nearly perfectly ordered B-site terminated surface with only a small fraction of A-site (La,Ca)O termination. This is accompanied, however, by surface roughening at a mesoscopic length scale. The results suggest that oxygen has a strong link to the adatom mobility during growth. The effect of the oxygen pressure on dopant surface segregation is also pronounced: Ca surface segregation is decreased with oxygen pressure reduction.
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Affiliation(s)
- Alexander Tselev
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Rama K Vasudevan
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | | - Liang Qiao
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - P Ganesh
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Tricia L Meyer
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ho Nyung Lee
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | | - Arthur P Baddorf
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sergei V Kalinin
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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Vaz CAF, Walker FJ, Ahn CH, Ismail-Beigi S. Intrinsic interfacial phenomena in manganite heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:123001. [PMID: 25721578 DOI: 10.1088/0953-8984/27/12/123001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We review recent advances in our understanding of interfacial phenomena that emerge when dissimilar materials are brought together at atomically sharp and coherent interfaces. In particular, we focus on phenomena that are intrinsic to the interface and review recent work carried out on perovskite manganites interfaces, a class of complex oxides whose rich electronic properties have proven to be a useful playground for the discovery and prediction of novel phenomena.
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Affiliation(s)
- C A F Vaz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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Magnetic interactions in BiFe₀.₅Mn₀.₅O₃ films and BiFeO₃/BiMnO₃ superlattices. Sci Rep 2015; 5:9093. [PMID: 25766744 PMCID: PMC4357900 DOI: 10.1038/srep09093] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 02/18/2015] [Indexed: 12/04/2022] Open
Abstract
The clear understanding of exchange interactions between magnetic ions in substituted BiFeO3 is the prerequisite for the comprehensive studies on magnetic properties. BiFe0.5Mn0.5O3 films and BiFeO3/BiMnO3 superlattices have been fabricated by pulsed laser deposition on (001) SrTiO3 substrates. Using piezoresponse force microscopy (PFM), the ferroelectricity at room temperature has been inferred from the observation of PFM hysteresis loops and electrical writing of ferroelectric domains for both samples. Spin glass behavior has been observed in both samples by temperature dependent magnetization curves and decay of thermo-remnant magnetization with time. The magnetic ordering has been studied by X-ray magnetic circular dichroism measurements, and Fe-O-Mn interaction has been confirmed to be antiferromagnetic (AF). The observed spin glass in BiFe0.5Mn0.5O3 films has been attributed to cluster spin glass due to Mn-rich ferromagnetic (FM) clusters in AF matrix, while spin glass in BiFeO3/BiMnO3 superlattices is due to competition between AF Fe-O-Fe, AF Fe-O-Mn and FM Mn-O-Mn interactions in the well ordered square lattice with two Fe ions in BiFeO3 layer and two Mn ions in BiMnO3 layer at interfaces.
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25
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Sung KD, Lee TK, Jung JH. Intriguing photo-control of exchange bias in BiFeO3/La2/3Sr1/3MnO3 thin films on SrTiO3 substrates. NANOSCALE RESEARCH LETTERS 2015; 10:125. [PMID: 25852417 PMCID: PMC4385218 DOI: 10.1186/s11671-015-0824-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/17/2015] [Indexed: 06/04/2023]
Abstract
To date, electric fields have been widely used to control the magnetic properties of BiFeO3-based antiferromagnet/ferromagnet heterostructures through application of an exchange bias. To extend the applicability of exchange bias, however, an alternative mechanism to electric fields is required. Here, we report the photo-control of exchange bias in BiFeO3/La2/3Sr1/3MnO3 thin films on an SrTiO3 substrate. Through an ex situ pulsed laser deposition technique, we successfully synthesized epitaxial BiFeO3/La2/3Sr1/3MnO3 thin films on SrTiO3 substrates. By measuring magnetoresistance under light illumination, we investigated the effect of light illumination on resistance, exchange bias, and coercive field in BiFeO3/La2/3Sr1/3MnO3 thin films. After illumination of red and blue lights, the exchange bias was sharply reduced compared to that measured in the dark. With increasing light intensity, the exchange bias under red and blue lights initially decreased to zero and then appeared again. It is possible to reasonably explain these behaviors by considering photo-injection from SrTiO3 and the photo-conductivity of La2/3Sr1/3MnO3. This study may provide a fundamental understanding of the mechanism underlying photo-controlled exchange bias, which is significant for the development of new functional spintronic devices.
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Affiliation(s)
- Kil Dong Sung
- Department of Physics, Inha University, Incheon, 402-751 Republic of Korea
| | - Tae Kwon Lee
- Department of Physics, Inha University, Incheon, 402-751 Republic of Korea
| | - Jong Hoon Jung
- Department of Physics, Inha University, Incheon, 402-751 Republic of Korea
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Chand Verma K, Tripathi SK, Kotnala RK. Magneto-electric/dielectric and fluorescence effects in multiferroic xBaTiO3–(1 − x)ZnFe2O4 nanostructures. RSC Adv 2014. [DOI: 10.1039/c4ra09625h] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Magneto-electric/dielectric and photoemission of BTZF composites depends upon shape, size, surface spin, distortion, epitaxial strain etc. of nanostructure
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Affiliation(s)
- Kuldeep Chand Verma
- Centre of Advanced Study in Physics
- Department of Physics
- Panjab University
- Chandigarh 160 014, India
| | - S. K. Tripathi
- Centre of Advanced Study in Physics
- Department of Physics
- Panjab University
- Chandigarh 160 014, India
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