Magnetization dynamics with a spin-transfer torque

被引:258
作者
Li, Z [1 ]
Zhang, S [1 ]
机构
[1] Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA
基金
美国国家科学基金会;
关键词
D O I
10.1103/PhysRevB.68.024404
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The magnetization reversal and dynamics of a spin valve pillar, whose lateral size is 64X64 nm(2), are studied by using micromagnetic simulation in the presence of spin-transfer torque. Spin torques display both characteristics of magnetic damping (or antidamping) and of an effective magnetic field. For a steady-state current, both M-I and M-H hysteresis loops show unique features, including multiple jumps, unusual plateaus, and precessional states. These states originate from the competition between the energy dissipation due to Gilbert damping and the energy accumulation due to the spin torque supplied by the spin current. The magnetic energy oscillates as a function of time even for a steady-state current. For a pulsed current, the minimum width and amplitude of the spin torque for achieving current-driven magnetization reversal are quantitatively determined. The spin torque also shows very interesting thermal activation that is fundamentally different from an ordinary damping effect.
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页数:10
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