The influence of thermal activation and the intrinsic temperature dependence of the spin torque effect in current-induced domain wall motion
The influence of thermal activation and the intrinsic temperature dependence of the spin torque effect in current-induced domain wall motion
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电流引起的磁畴壁运动中热激活的影响和自旋扭矩效应的固有温度依赖性
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
U. Rüdiger
中科院分区：
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作者：
P. Dagras;M. Kläui;M. Laufenberg;D. Bedau;L. Vila;G. Faini;C. Vaz;J. Bland;U. Rüdiger
对电流脉冲和常规磁场共同作用下Ni80Fe20环结构中的磁畴壁运动进行了实验研究。利用约束，我们证明了电流诱导的磁区壁运动可以用来将磁区壁位移到结构中没有脉冲电流流动的部分。在2~300 K温度范围内的测量表明，壁面运动所需的磁场随着温度的升高而减小，这可以用热激活来解释。对于电流感应的情况，我们发现，位移所需的电流密度可以随着温度的升高而增加或减少，具体取决于几何形状和温度范围。这表明，除了热激发外，自旋扭矩效应的效率还与温度存在内在的依赖关系，并导致临界电流密度随温度升高而增加。
An experimental study of domain wall motion in Ni80Fe20 ring structures induced by current pulses as well as conventional magnetic fields is presented. Using constrictions we demonstrate that current-induced domain wall motion can be used to displace walls into parts of the structure where no pulsed currents are flowing. Measurements at variable temperatures between 2 and 300 K show that the fields necessary for wall motion decrease with increasing temperature, which can be explained by thermal activation. For the current-induced case we find, depending on the geometry and temperature range, that the current densities necessary for displacement can increase or decrease with rising temperature. This indicates that, in addition to thermal excitations, an intrinsic temperature dependence of the efficiency of the spin torque effect is present and leads to an increase in the critical current density with increasing temperature.