Thermally assisted spin transfer torque switching in synthetic free layers
Thermally assisted spin transfer torque switching in synthetic free layers
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DOI：
10.1103/physrevb.83.054432
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发表时间：
2010-10
影响因子：
3.7
通讯作者：
T. Taniguchi;H. Imamura
中科院分区：
文献类型：
--
作者：
T. Taniguchi;H. Imamura
从理论上研究了铁磁耦合合成自由层中热辅助自旋转移矩翻转的磁化反转率。通过求解Fokker-Planck方程，得到了弱耦合和强耦合极限下开关几率的解析表达式。我们发现热稳定性与Δ_{0}（1-I/I_{c}）^{2}成正比，而不是Koch等人[Phys.Rev.Lett. 92，088302（2004）]，其中I和I_{c}是在绝对零度温度下自旋转移矩切换的电流和临界电流。（1-I/I_{c}）指数的差异导致对热稳定性Δ_{0}的显著低估。我们还发现，快速开关是通过选择适当的方向的应用领域。
We studied the magnetization reversal rates of thermally assisted spin transfer torque switching in a ferromagnetically coupled synthetic free layer theoretically. By solving the Fokker-Planck equation, we obtained the analytical expression of the switching probability for both the weak and the strong coupling limit. We found that the thermal stability is proportional to Delta_{0}(1-I/I_{c})^{2}, not Delta_{0}(1-I/I_{c}) argued by Koch et al. [Phys. Rev. Lett. 92, 088302 (2004)], where I and I_{c} are the electric current and the critical current of spin transfer torque switching at absolute zero temperature. The difference in the exponent of (1-I/I_{c}) leads to a significant underestimation of the thermal stability Delta_{0}. We also found that fast switching is achieved by choosing the appropriate direction of the applied field.