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Zhang X, Wang C, Liu Y, Zhang Z, Jin QY, Duan CG. Magnetization switching by combining electric field and spin-transfer torque effects in a perpendicular magnetic tunnel junction. Sci Rep 2016; 6:18719. [PMID: 26732287 PMCID: PMC4702111 DOI: 10.1038/srep18719] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/25/2015] [Indexed: 11/09/2022] Open
Abstract
Effective manipulation of magnetization orientation driven by electric field in a perpendicularly magnetized tunnel junction introduces technologically relevant possibility for developing low power magnetic memories. However, the bipolar orientation characteristic of toggle-like magnetization switching possesses intrinsic difficulties for practical applications. By including both the in-plane (T//) and field-like (T⊥) spin-transfer torque terms in the Landau-Lifshitz-Gilbert simulation, reliable and deterministic magnetization reversal can be achieved at a significantly reduced current density of 5×10(9) A/m(2) under the co-action of electric field and spin-polarized current, provided that the electric-field pulse duration exceeds a certain critical value τc. The required critical τc decreases with the increase of T⊥ strength because stronger T⊥ can make the finally stabilized out-of-plane component of magnetization stay in a larger negative value. The power consumption for such kind of deterministic magnetization switching is found to be two orders of magnitude lower than that of the switching driven by current only.
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Affiliation(s)
- Xiangli Zhang
- Department of Optical Science and Engineering, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China
| | - Chengjie Wang
- School of Physical Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yaowen Liu
- School of Physical Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zongzhi Zhang
- Department of Optical Science and Engineering, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China
| | - Q. Y. Jin
- Department of Optical Science and Engineering, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China
| | - Chun-Gang Duan
- Key Laboratory of Polar Materials and Devices, Ministry of Education East China Normal University, Shanghai 200062, China
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Zeng T, Zhou Y, Leung CW, Lai PPT, Pong PWT. Capacitance effect on the oscillation and switching characteristics of spin torque oscillators. NANOSCALE RESEARCH LETTERS 2014; 9:597. [PMID: 25404870 PMCID: PMC4230906 DOI: 10.1186/1556-276x-9-597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/07/2014] [Indexed: 06/04/2023]
Abstract
We have studied the capacitance effect on the oscillation characteristics and the switching characteristics of the spin torque oscillators (STOs). We found that when the external field is applied, the STO oscillation frequency exhibits various dependences on the capacitance for injected current ranging from 8 to 20 mA. The switching characteristic is featured with the emerging of the canted region; the canted region increases with the capacitance. When the external field is absent, the STO free-layer switching time exhibits different dependences on the capacitance for different injected current. These results help to establish the foundation for capacitance-involved STO modeling.
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Affiliation(s)
- Tui Zeng
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong
| | - Yan Zhou
- Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
| | - Chi Wah Leung
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Peter PT Lai
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong
| | - Philip WT Pong
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong
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He PB. Current-driven domain wall dynamics in spin-valve nanostrips with parallel, perpendicular, and tilted polarizers. THE EUROPEAN PHYSICAL JOURNAL B 2013; 86:412. [DOI: 10.1140/epjb/e2013-40472-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Kim J, Sinha J, Hayashi M, Yamanouchi M, Fukami S, Suzuki T, Mitani S, Ohno H. Layer thickness dependence of the current-induced effective field vector in Ta|CoFeB|MgO. NATURE MATERIALS 2013; 12:240-5. [PMID: 23263641 DOI: 10.1038/nmat3522] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 11/13/2012] [Indexed: 05/17/2023]
Abstract
Current-induced effective magnetic fields can provide efficient ways of electrically manipulating the magnetization of ultrathin magnetic heterostructures. Two effects, known as the Rashba spin orbit field and the spin Hall spin torque, have been reported to be responsible for the generation of the effective field. However, a quantitative understanding of the effective field, including its direction with respect to the current flow, is lacking. Here we describe vector measurements of the current-induced effective field in Ta|CoFeB|MgO heterostructrures. The effective field exhibits a significant dependence on the Ta and CoFeB layer thicknesses. In particular, a 1 nm thickness variation of the Ta layer can change the magnitude of the effective field by nearly two orders of magnitude. Moreover, its sign changes when the Ta layer thickness is reduced, indicating that there are two competing effects contributing to it. Our results illustrate that the presence of atomically thin metals can profoundly change the landscape for controlling magnetic moments in magnetic heterostructures electrically.
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Affiliation(s)
- Junyeon Kim
- National Institute for Materials Science, Tsukuba 305-0047, Japan
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Ralph DC, Cui YT, Liu LQ, Moriyama T, Wang C, Buhrman RA. Spin-transfer torque in nanoscale magnetic devices. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:3617-3630. [PMID: 21859725 DOI: 10.1098/rsta.2011.0169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We discuss recent highlights from research at Cornell University, Ithaca, New York, regarding the use of spin-transfer torques to control magnetic moments in nanoscale ferromagnetic devices. We highlight progress on reducing the critical currents necessary to produce spin-torque-driven magnetic switching, quantitative measurements of the magnitude and direction of the spin torque in magnetic tunnel junctions, and single-shot measurements of the magnetic dynamics generated during thermally assisted spin-torque switching.
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Affiliation(s)
- D C Ralph
- Cornell University, Ithaca, New York, NY 14853, USA.
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Suzuki Y, Kubota H, Tulapurkar A, Nozaki T. Spin control by application of electric current and voltage in FeCo-MgO junctions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:3658-3678. [PMID: 21859728 DOI: 10.1098/rsta.2011.0190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Efficient control and detection of spins are the most important tasks in spintronics. The current and voltage applied to a magnetic tunnel junction may exert a torque on the magnetic thin layer in the junction and cause its reversal or continuous precession. The discovery of the giant tunnelling magnetoresistance effect in ferromagnetic tunnelling junctions using an MgO barrier enabled us to obtain a large signal output from the magnetization reversal and precession. Also, the interplay of large spin configuration-electric conduction coupling provides highly nonlinear effects like the spin-torque diode effect. The negative resistance effect and amplification using it are predicted. A new discovery about a voltage-induced magnetic anisotropy change in Fe ultrathin films is also discussed.
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Affiliation(s)
- Yoshishige Suzuki
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
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Zhou B, Chen X, Zhou B, Ding KH, Zhou G. Spin-dependent transport for armchair-edge graphene nanoribbons between ferromagnetic leads. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:135304. [PMID: 21415476 DOI: 10.1088/0953-8984/23/13/135304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We theoretically investigate the spin-dependent transport for the system of an armchair-edge graphene nanoribbon (AGNR) between two ferromagnetic (FM) leads with arbitrary polarization directions at low temperatures, where a magnetic insulator is deposited on the AGNR to induce an exchange splitting between spin-up and -down carriers. By using the standard nonequilibrium Green's function (NGF) technique, it is demonstrated that the spin-resolved transport property for the system depends sensitively on both the width of AGNR and the polarization strength of FM leads. The tunneling magnetoresistance (TMR) around zero bias voltage possesses a pronounced plateau structure for a system with semiconducting 7-AGNR or metallic 8-AGNR in the absence of exchange splitting, but this plateau structure for the 8-AGNR system is remarkably broader than that for the 7-AGNR one. Interestingly, an increase of the exchange splitting Δ suppresses the amplitude of the structure for the 7-AGNR system. However, the TMR is much enhanced for the 8-AGNR system under a bias amplitude comparable to the splitting strength. Further, the current-induced spin-transfer torque (STT) for the 7-AGNR system is systematically larger than that for the 8-AGNR one. The findings here suggest the design of GNR-based spintronic devices by using a metallic AGNR, but it is more favorable to fabricate a current-controlled magnetic memory element by using a semiconducting AGNR.
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Affiliation(s)
- Benhu Zhou
- Department of Physics and Key Laboratory for Low-Dimensional Structures and Quantum Manipulation (Ministry of Education), Hunan Normal University, Changsha, People's Republic of China
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Heinonen OG, Stokes SW, Yi JY. Perpendicular spin torque in magnetic tunnel junctions. PHYSICAL REVIEW LETTERS 2010; 105:066602. [PMID: 20867995 DOI: 10.1103/physrevlett.105.066602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 06/23/2010] [Indexed: 05/29/2023]
Abstract
A steady-state electrical current flowing in a magnetic heterostructure can exert a torque on the magnetization, and provides a means to control magnetization states and dynamics in spintronics structures. However, some components of the torque are difficult to measure and to calculate. We have determined the perpendicular spin torque in MgO magnetic tunnel junctions by measuring their lowest ferromagnetic resonance frequency and find that it decreases linearly with increasing bias voltage. Micromagnetic modeling shows that this decrease is caused by the perpendicular component of spin torque. We obtain a quantitative value for the perpendicular spin torque effective field as a function of bias voltage, and show that this effective field is a linear function in bias voltage and approximately equal in magnitude to the in-plane spin torque effective field.
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Affiliation(s)
- O G Heinonen
- Recording Heads Operation, Seagate Technology, 7801 Computer Ave, Bloomington, Minnesota 55435, USA.
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Tang YH, Kioussis N, Kalitsov A, Butler WH, Car R. Controlling the nonequilibrium interlayer exchange coupling in asymmetric magnetic tunnel junctions. PHYSICAL REVIEW LETTERS 2009; 103:057206. [PMID: 19792533 DOI: 10.1103/physrevlett.103.057206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Indexed: 05/28/2023]
Abstract
We predict an oscillatory bias behavior of the fieldlike spin torque, T(perpendicular), in magnetic tunnel junctions, which can be selectively controlled via the asymmetry in band filling between the ferromagnetic leads. This can lead to a linear or quadratic low-bias behavior, including tuning the bias-induced reversal of T(perpendicular). These findings reconcile the apparently contradictory experimental results recently reported in the literature. The underlying mechanism for the nonequilibrium interlayer exchange coupling (IEC) of noncollinear configurations is the interplay of four independent IEC for the majority- and minority-spin bands of the leads solely in the ferromagnetic configuration.
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Affiliation(s)
- Y-H Tang
- Department of Physics, California State University, Northridge, California 91330-8268, USA
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