1
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Wang P, Jin C, Li D, Wang Y, Liu S, Wang X, Pang X, Zheng D, Zheng W, Zheng R, Bai H. Electric-field-mediated magnetic properties of all-oxide CoFe 2O 4/La 0.67Sr 0.33MnO 3/Pb(Mg 1/3Nb 2/3) 0.7Ti 0.3O 3 heterostructures. Phys Chem Chem Phys 2020; 22:12651-12657. [DOI: 10.1039/d0cp01374a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The coercivity of the CFO/LSMO/PMN-PT heterostructures decreases ∼50%, making it possible to achieve electric-field-controlled magnetoresistance.
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2
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Tornos J, Gallego F, Valencia S, Liu YH, Rouco V, Lauter V, Abrudan R, Luo C, Ryll H, Wang Q, Hernandez-Martin D, Orfila G, Cabero M, Cuellar F, Arias D, Mompean FJ, Garcia-Hernandez M, Radu F, Charlton TR, Rivera-Calzada A, Sefrioui Z, Te Velthuis SGE, Leon C, Santamaria J. Ferroelectric Control of Interface Spin Filtering in Multiferroic Tunnel Junctions. PHYSICAL REVIEW LETTERS 2019; 122:037601. [PMID: 30735408 DOI: 10.1103/physrevlett.122.037601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/27/2018] [Indexed: 06/09/2023]
Abstract
The electronic reconstruction occurring at oxide interfaces may be the source of interesting device concepts for future oxide electronics. Among oxide devices, multiferroic tunnel junctions are being actively investigated as they offer the possibility to modulate the junction current by independently controlling the switching of the magnetization of the electrodes and of the ferroelectric polarization of the barrier. In this Letter, we show that the spin reconstruction at the interfaces of a La_{0.7}Sr_{0.3}MnO_{3}/BaTiO_{3}/La_{0.7}Sr_{0.3}MnO_{3} multiferroic tunnel junction is the origin of a spin filtering functionality that can be turned on and off by reversing the ferroelectric polarization. The ferroelectrically controlled interface spin filter enables a giant electrical modulation of the tunneling magnetoresistance between values of 10% and 1000%, which could inspire device concepts in oxides-based low dissipation spintronics.
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Affiliation(s)
- J Tornos
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - F Gallego
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - S Valencia
- Hemholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Y H Liu
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee 37831, USA
- Argonne National Laboratory, Materials Science Division, Argonne, Illinois 60439, USA
| | - V Rouco
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - V Lauter
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee 37831, USA
| | - R Abrudan
- Hemholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Institut für Experimentalphysik (Festkörperphysik), Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - C Luo
- Hemholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - H Ryll
- Hemholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Q Wang
- Argonne National Laboratory, Materials Science Division, Argonne, Illinois 60439, USA
| | | | - G Orfila
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - M Cabero
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - F Cuellar
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - D Arias
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - F J Mompean
- 2D-Foundry Group, Instituto de Ciencia de Materiales de Madrid ICMM-CSIC, 28049 Madrid, Spain
- Laboratorio de Heteroestructuras con aplicación en spintrónica, Unidad Asociada UCM/CSIC, 28049 Madrid, Spain
| | - M Garcia-Hernandez
- 2D-Foundry Group, Instituto de Ciencia de Materiales de Madrid ICMM-CSIC, 28049 Madrid, Spain
- Laboratorio de Heteroestructuras con aplicación en spintrónica, Unidad Asociada UCM/CSIC, 28049 Madrid, Spain
| | - F Radu
- Hemholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - T R Charlton
- ISIS, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom
| | - A Rivera-Calzada
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Laboratorio de Heteroestructuras con aplicación en spintrónica, Unidad Asociada UCM/CSIC, 28049 Madrid, Spain
| | - Z Sefrioui
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Laboratorio de Heteroestructuras con aplicación en spintrónica, Unidad Asociada UCM/CSIC, 28049 Madrid, Spain
- GFMC, Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - S G E Te Velthuis
- Argonne National Laboratory, Materials Science Division, Argonne, Illinois 60439, USA
| | - C Leon
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Laboratorio de Heteroestructuras con aplicación en spintrónica, Unidad Asociada UCM/CSIC, 28049 Madrid, Spain
- GFMC, Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - J Santamaria
- GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Laboratorio de Heteroestructuras con aplicación en spintrónica, Unidad Asociada UCM/CSIC, 28049 Madrid, Spain
- GFMC, Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid, 28040 Madrid, Spain
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3
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Anisotropic sensor and memory device with a ferromagnetic tunnel barrier as the only magnetic element. Sci Rep 2018; 8:861. [PMID: 29339784 PMCID: PMC5770439 DOI: 10.1038/s41598-017-19129-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/21/2017] [Indexed: 11/08/2022] Open
Abstract
Multiple spin functionalities are probed on Pt/La2Co0.8Mn1.2O6/Nb:SrTiO3, a device composed by a ferromagnetic insulating barrier sandwiched between non-magnetic electrodes. Uniquely, La2Co0.8Mn1.2O6 thin films present strong perpendicular magnetic anisotropy of magnetocrystalline origin, property of major interest for spintronics. The junction has an estimated spin-filtering efficiency of 99.7% and tunneling anisotropic magnetoresistance (TAMR) values up to 30% at low temperatures. This remarkable angular dependence of the magnetoresistance is associated with the magnetic anisotropy whose origin lies in the large spin-orbit interaction of Co2+ which is additionally tuned by the strain of the crystal lattice. Furthermore, we found that the junction can operate as an electrically readable magnetic memory device. The findings of this work demonstrate that a single ferromagnetic insulating barrier with strong magnetocrystalline anisotropy is sufficient for realizing sensor and memory functionalities in a tunneling device based on TAMR.
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4
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Li P, Xia C, Li J, Zhu Z, Wen Y, Zhang Q, Zhang J, Peng Y, Alshareef HN, Zhang X. Spin Filtering in Epitaxial Spinel Films with Nanoscale Phase Separation. ACS NANO 2017; 11:5011-5019. [PMID: 28480708 DOI: 10.1021/acsnano.7b01743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The coexistence of ferromagnetic metallic phase and antiferromagnetic insulating phase in nanoscaled inhomogeneous perovskite oxides accounts for the colossal magnetoresistance. Although the model of spin-polarized electron transport across antiphase boundaries has been commonly employed to account for large magnetoresistance (MR) in ferrites, the magnetic anomalies, the two magnetic phases and enhanced molecular moment, are still unresolved. We observed a sizable MR in epitaxial spinel films (NiCo2O4-δ) that is much larger than that commonly observed in spinel ferrites. Detailed analysis reveals that this MR can be attributed to phase separation, in which the perfect ferrimagnetic metallic phase and ferrimagnetic insulating phase coexist. The magnetic insulating phase plays an important role in spin filtering in these phase separated spinel oxides, leading to a sizable MR effect. A spin filtering model based on Zeeman effect and direct tunneling is developed to account for MR of the phase separated films.
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Affiliation(s)
- Peng Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Chuan Xia
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Jun Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Zhiyong Zhu
- KAUST Supercomputing Laboratory (KSL), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Yan Wen
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Qiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Junwei Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Yong Peng
- Key Laboratory of Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University , Lanzhou 730000, Gansu, PR China
| | - Husam N Alshareef
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Xixiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
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5
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Tang YH, Chu FC, Kioussis N. Dual Control of Giant Field-like Spin Torque in Spin Filter Tunnel Junctions. Sci Rep 2015; 5:11341. [PMID: 26095146 PMCID: PMC4476168 DOI: 10.1038/srep11341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/20/2015] [Indexed: 11/28/2022] Open
Abstract
We predict a giant field-like spin torque, , in spin-filter (SF) barrier tunnel junctions in sharp contrast to existing junctions based on nonmagnetic passive barriers. We demonstrate that has linear bias behavior, is independent of the SF thickness, and has odd parity with respect to the SF’s exchange splitting. Thus, it can be selectively controlled via external bias or external magnetic field which gives rise to sign reversal of via magnetic field switching. The underlying mechanism is the interlayer exchange coupling between the noncollinear magnetizations of the SF and free ferromagnetic electrode via the nonmagnetic insulating (I) spacer giving rise to giant spin-dependent reflection at the SF/I interface. These findings suggest that the proposed field-like-spin-torque MRAM may provide promising dual functionalities for both ‘reading’ and ‘writing’ processes which require lower critical current densities and faster writing and reading speeds.
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Affiliation(s)
- Y-H Tang
- Department of Physics, National Central University, Jung-Li 32001, Taiwan
| | - F-C Chu
- Department of Physics, National Central University, Jung-Li 32001, Taiwan
| | - Nicholas Kioussis
- Department of Physics, California State University, Northridge, CA 91330-8268, USA
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6
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Prasad B, Zhang W, Jian J, Wang H, Blamire MG. Strongly bias-dependent tunnel magnetoresistance in manganite spin filter tunnel junctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:3079-3084. [PMID: 25845706 DOI: 10.1002/adma.201405147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 03/12/2015] [Indexed: 06/04/2023]
Abstract
A highly unconventional bias-dependent tunnel magnetoresistance (TMR) response is observed in Sm0.75 Sr0.25 MnO3 -based nanopillar spin filter tunnel junctions (SFTJs) with two different behaviors in two different thickness regimes of the barrier layer. Thinner barrier devices exhibit conventional SFTJ behaviors; however, for larger barrier thicknesses, the TMR-bias dependence is more complex and reverses sign at higher bias.
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Affiliation(s)
- Bhagwati Prasad
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Wenrui Zhang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843-3128, USA
| | - Jie Jian
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843-3128, USA
| | - Haiyan Wang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843-3128, USA
| | - Mark G Blamire
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
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7
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Bruno FY, Grisolia MN, Visani C, Valencia S, Varela M, Abrudan R, Tornos J, Rivera-Calzada A, Ünal AA, Pennycook SJ, Sefrioui Z, Leon C, Villegas JE, Santamaria J, Barthélémy A, Bibes M. Insight into spin transport in oxide heterostructures from interface-resolved magnetic mapping. Nat Commun 2015; 6:6306. [PMID: 25686532 DOI: 10.1038/ncomms7306] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 01/15/2015] [Indexed: 11/09/2022] Open
Abstract
At interfaces between complex oxides, electronic, orbital and magnetic reconstructions may produce states of matter absent from the materials involved, offering novel possibilities for electronic and spintronic devices. Here we show that magnetic reconstruction has a strong influence on the interfacial spin selectivity, a key parameter controlling spin transport in magnetic tunnel junctions. In epitaxial heterostructures combining layers of antiferromagnetic LaFeO(3) (LFO) and ferromagnetic La(0.7)Sr(0.3)MnO(3) (LSMO), we find that a net magnetic moment is induced in the first few unit planes of LFO near the interface with LSMO. Using X-ray photoemission electron microscopy, we show that the ferromagnetic domain structure of the manganite electrodes is imprinted into the antiferromagnetic tunnel barrier, endowing it with spin selectivity. Finally, we find that the spin arrangement resulting from coexisting ferromagnetic and antiferromagnetic interactions strongly influences the tunnel magnetoresistance of LSMO/LFO/LSMO junctions through competing spin-polarization and spin-filtering effects.
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Affiliation(s)
- F Y Bruno
- Unité Mixte de Physique CNRS/Thales, 1 Avenue A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - M N Grisolia
- Unité Mixte de Physique CNRS/Thales, 1 Avenue A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - C Visani
- Unité Mixte de Physique CNRS/Thales, 1 Avenue A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - S Valencia
- Helmholtz-Zentrum-Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - M Varela
- 1] GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain [2] Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain [3] Materials Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R Abrudan
- 1] Helmholtz-Zentrum-Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany [2] Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - J Tornos
- 1] GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain [2] Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - A Rivera-Calzada
- 1] GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain [2] Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - A A Ünal
- Helmholtz-Zentrum-Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - S J Pennycook
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Z Sefrioui
- 1] GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain [2] Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - C Leon
- 1] GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain [2] Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - J E Villegas
- Unité Mixte de Physique CNRS/Thales, 1 Avenue A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - J Santamaria
- 1] GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain [2] Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - A Barthélémy
- Unité Mixte de Physique CNRS/Thales, 1 Avenue A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - M Bibes
- Unité Mixte de Physique CNRS/Thales, 1 Avenue A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
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8
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Lin H, Luo Q, Tong WY, Jiang C, Huang R, Peng H, Zhang LC, Travas-Sejdic J, Duan CG. Facile preparation of rare-earth semiconductor nanocrystals and tuning of their dimensionalities. RSC Adv 2015. [DOI: 10.1039/c5ra17506b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Monodispersed EuS and Gd2O2S nanocrystals are synthesized in high yields by the thermal decomposition of Eu(oleate)3 or Gd(oleate)3 by using CS2 as the sulfur source with an advantage of facile tuning their dimensionality.
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Affiliation(s)
- Hechun Lin
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
| | - Qianqian Luo
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
| | - Wen-Yi Tong
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
| | - Chunli Jiang
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
| | - Rong Huang
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
| | - Hui Peng
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
| | | | | | - Chun-Gang Duan
- Key Laboratory of Polar Materials and Devices
- Ministry of Education
- East China Normal University
- Shanghai
- China
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9
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Miao GX, Moodera JS. Spin manipulation with magnetic semiconductor barriers. Phys Chem Chem Phys 2015; 17:751-61. [DOI: 10.1039/c4cp04599h] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic semiconductors with unique spin-filtering property and the ability to create excessive internal magnetic fields can open myriads of new phenomena.
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Affiliation(s)
- Guo-Xing Miao
- Institute for Quantum
- Computing and Department of Electrical and Computer Engineering
- University of Waterloo
- Waterloo
- Canada
| | - Jagadeesh S. Moodera
- Francis Bitter Magnet Laboratory
- Massachusetts Institute of Technology
- Cambridge
- USA
- Department of Physics
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10
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Dhungana KB, Pati R. Boron nitride nanotubes for spintronics. SENSORS (BASEL, SWITZERLAND) 2014; 14:17655-85. [PMID: 25248070 PMCID: PMC4208243 DOI: 10.3390/s140917655] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/03/2014] [Indexed: 11/17/2022]
Abstract
With the end of Moore's law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR) effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT), which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics.
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Affiliation(s)
- Kamal B Dhungana
- Department of Physics, Michigan Technological University, Houghton, MI 49931, USA.
| | - Ranjit Pati
- Department of Physics, Michigan Technological University, Houghton, MI 49931, USA.
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11
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Spin regulation in composite spin-filter barrier devices. Nat Commun 2014; 5:3682. [PMID: 24759596 DOI: 10.1038/ncomms4682] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 03/18/2014] [Indexed: 11/09/2022] Open
Abstract
Magnetic insulators are known to provide large effective Zeeman fields that are confined at an interface, making them especially powerful in modifying adjacent one- or two-dimensional electronic structures. Utilizing this phenomenon and the other important property of magnetic insulators--spin filtering--here we report the generation and subsequent detection of a large interface field, as large as tens of tesla in EuS/Al/EuS heterostructures with metallic coulomb islands confined within a magnetic insulator barrier. The unique energy profile across this sandwich structure produces spin-assisted charge transfer across the device, generating a spontaneous spin current and voltage. These unique properties can be practical for controlling spin flows in electronic devices and for energy harvesting.
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12
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Galanakis I, Özdoğan K, Şaşıoglu E. High-T C fully compensated ferrimagnetic semiconductors as spin-filter materials: the case of CrVXAl (X = Ti, Zr, Hf) Heusler compounds. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:086003. [PMID: 24501208 DOI: 10.1088/0953-8984/26/8/086003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We extend our recent work on spin-filter materials (Galanakis et al 2013 Appl. Phys. Lett.103 142404) to the case of CrVXAl (X = Ti, Zr, Hf) compounds, for which, using ab initio electronic structure calculations, we show that p-d hybridization leads to the formation of a fully compensated ferrimagnetic semiconducting state with moderate exchange splitting. The magnetism is of covalent-type and the very strong antiferromagnetic Cr-V exchange interactions lead to extremely high Curie temperature, TC, values. Furthermore, all three compounds are thermodynamically and magnetically stable. The combination of very high TC values with a zero total net magnetization makes them promising materials for spintronics applications.
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Affiliation(s)
- I Galanakis
- Department of Materials Science, School of Natural Sciences, University of Patras, Patras 26504, Greece
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13
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Liu Y, Cuellar FA, Sefrioui Z, Freeland JW, Fitzsimmons MR, Leon C, Santamaria J, te Velthuis SGE. Emergent spin filter at the interface between ferromagnetic and insulating layered oxides. PHYSICAL REVIEW LETTERS 2013; 111:247203. [PMID: 24483696 DOI: 10.1103/physrevlett.111.247203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Indexed: 06/03/2023]
Abstract
We report a strong effect of interface-induced magnetization on the transport properties of magnetic tunnel junctions consisting of ferromagnetic manganite La0.7Ca0.3MnO3 and insulating cuprate PrBa2Cu3O7. Contrary to the typically observed steady increase of the tunnel magnetoresistance with decreasing temperature, this system exhibits a sudden anomalous decrease at low temperatures. Interestingly, this anomalous behavior can be attributed to the competition between the positive spin polarization of the manganite contacts and the negative spin-filter effect from the interface-induced Cu magnetization.
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Affiliation(s)
- Yaohua Liu
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - F A Cuellar
- GFMC, Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, Campus Moncloa, ES-28040 Madrid, Spain
| | - Z Sefrioui
- GFMC, Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, Campus Moncloa, ES-28040 Madrid, Spain
| | - J W Freeland
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M R Fitzsimmons
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Leon
- GFMC, Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, Campus Moncloa, ES-28040 Madrid, Spain
| | - J Santamaria
- GFMC, Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, Campus Moncloa, ES-28040 Madrid, Spain
| | - S G E te Velthuis
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Pal A, Senapati K, Barber ZH, Blamire MG. Electric-field-dependent spin polarization in GdN spin filter tunnel junctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:5581-5585. [PMID: 23893892 DOI: 10.1002/adma.201300636] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 06/02/2013] [Indexed: 06/02/2023]
Abstract
Tunnel junctions incorporating GdN ferromagnetic semiconductor barriers show a spin polarization exceeding 90% and a high conductance. These devices show an unusual low-bias conductance peak arising from a strong bias-dependence of the spin polarization. This originates from a strong magneto-electric coupling within a double Schottky barrier formed with the NbN electrodes.
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Affiliation(s)
- Avradeep Pal
- Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, UK
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15
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16
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Sefrioui Z, Visani C, Calderón MJ, March K, Carrétéro C, Walls M, Rivera-Calzada A, León C, Anton RL, Charlton TR, Cuellar FA, Iborra E, Ott F, Imhoff D, Brey L, Bibes M, Santamaria J, Barthélémy A. All-manganite tunnel junctions with interface-induced barrier magnetism. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:5029-5034. [PMID: 20824666 DOI: 10.1002/adma.201002067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Z Sefrioui
- Grupo de Física de Materiales Complejos, Universidad Complutense de Madrid, 28040 Madrid, Spain
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17
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Miao GX, Müller M, Moodera JS. Magnetoresistance in double spin filter tunnel junctions with nonmagnetic electrodes and its unconventional bias dependence. PHYSICAL REVIEW LETTERS 2009; 102:076601. [PMID: 19257701 DOI: 10.1103/physrevlett.102.076601] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Indexed: 05/27/2023]
Abstract
Spin filtering happens due to the discriminative tunneling probabilities for spin-up and spin-down electrons through a magnetic barrier and can result in highly spin polarized tunnel currents. Combining two such barriers in a tunnel junction thus leads to large magnetoresistance without the necessity of magnetic electrodes. We demonstrate the realization of such unconventional tunnel junctions using double EuS spin filter barriers with Al electrodes. The novel nonmonotonic and asymmetric bias behavior in magnetoresistance can be qualitatively modeled in the framework of WKB approximations.
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Affiliation(s)
- Guo-Xing Miao
- Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Müller GM, Walowski J, Djordjevic M, Miao GX, Gupta A, Ramos AV, Gehrke K, Moshnyaga V, Samwer K, Schmalhorst J, Thomas A, Hütten A, Reiss G, Moodera JS, Münzenberg M. Spin polarization in half-metals probed by femtosecond spin excitation. NATURE MATERIALS 2009; 8:56-61. [PMID: 19079243 DOI: 10.1038/nmat2341] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 10/21/2008] [Indexed: 05/27/2023]
Abstract
Knowledge of the spin polarization is of fundamental importance for the use of a material in spintronics applications. Here, we used femtosecond optical excitation of half-metals to distinguish between half-metallic and metallic properties. Because the direct energy transfer by Elliot-Yafet scattering is blocked in a half-metal, the demagnetization time is a measure for the degree of half-metallicity. We propose that this characteristic enables us vice versa to establish a novel and fast characterization tool for this highly important material class used in spin-electronic devices. The technique has been applied to a variety of materials where the spin polarization at the Fermi level ranges from 45 to 98%: Ni, Co(2)MnSi, Fe(3)O(4), La(0.66)Sr(0.33)MnO(3) and CrO(2).
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Affiliation(s)
- Georg M Müller
- IV. Phys. Institut, Universität Göttingen, D-37077 Göttingen, Germany
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Santos TS, Moodera JS, Raman KV, Negusse E, Holroyd J, Dvorak J, Liberati M, Idzerda YU, Arenholz E. Determining exchange splitting in a magnetic semiconductor by spin-filter tunneling. PHYSICAL REVIEW LETTERS 2008; 101:147201. [PMID: 18851564 DOI: 10.1103/physrevlett.101.147201] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Indexed: 05/26/2023]
Abstract
A large exchange splitting of the conduction band in ultrathin films of the ferromagnetic semiconductor EuO was determined quantitatively, by using EuO as a tunnel barrier and fitting the current-voltage characteristics and temperature dependence to tunneling theory. This exchange splitting leads to different tunnel barrier heights for spin-up and spin-down electrons and is large enough to produce a near-fully spin-polarized current. Moreover, the magnetic properties of these ultrathin films (<6 nm) show a reduction in Curie temperature with decreasing thickness, in agreement with theoretical calculation [R. Schiller, Phys. Rev. Lett. 86, 3847 (2001)10.1103/Phys. Rev. Lett.86.3847].
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Affiliation(s)
- T S Santos
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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