Thermally assisted magnetization reversal in the presence of a spin-transfer torque

被引:351
作者
Li, Z [1 ]
Zhang, S [1 ]
机构
[1] Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA
来源
PHYSICAL REVIEW B | 2004年 / 69卷 / 13期
关键词
D O I
10.1103/PhysRevB.69.134416
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We propose a generalized stochastic Landau-Lifshitz equation and its corresponding Fokker-Planck equation for the magnetization dynamics in the presence of spin-transfer torques. Since the spin-transfer torque can pump a magnetic energy into the magnetic system, the equilibrium temperature of the magnetic system is ill defined. We introduce an effective temperature based on a stationary solution of the Fokker-Planck equation. In the limit of high-energy barriers, the law of thermal agitation is derived. We find that the Neel-Brown relaxation formula remains valid as long as we replace the temperature by an effective one that is linearly dependent on the spin torque. We carry out the numerical integration of the stochastic Landau-Lifshitz equation to support our theory. Our results agree with existing experimental data.
引用
收藏
页码:134416 / 1
页数:6
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