Urazhdin S, Birge Norman O, Pratt W P, Bass J
Department of Physics and Astronomy, Center for Fundamental Materials Research and Center for Sensor Materials, Michigan State University, East Lansing, Michigan 48824, USA.
Phys Rev Lett. 2003 Oct 3;91(14):146803. doi: 10.1103/PhysRevLett.91.146803. Epub 2003 Oct 1.
We study current-driven magnetization switching in nanofabricated Ni(84)Fe(16)/Cu/Ni(84)Fe16 trilayers at 295 and 4.2 K. The shape of the hysteretic switching diagram at low magnetic field changes with temperature. The reversible behavior at higher fields involves two phenomena, a threshold current for magnetic excitations closely correlated with the switching current, and a peak in differential resistance characterized by telegraph noise, with an average period that decreases exponentially with current and shifts with temperature. We interpret both static and dynamic results at 295 and 4.2 K in terms of thermal activation over a potential barrier, with a current-dependent effective magnetic temperature.
我们研究了在295K和4.2K温度下，纳米制造的Ni(84)Fe(16)/Cu/Ni(84)Fe16三层膜中电流驱动的磁化翻转。低磁场下磁滞翻转图的形状随温度变化。较高磁场下的可逆行为涉及两种现象，一种是与翻转电流密切相关的磁激发阈值电流，另一种是由电报噪声表征的微分电阻峰值，其平均周期随电流呈指数下降并随温度变化。我们根据势垒上的热激活以及与电流相关的有效磁温度来解释295K和4.2K时的静态和动态结果。
