Magnetoresistance Dynamics in Superparamagnetic Co−Fe−B Nanodots
Magnetoresistance Dynamics in Superparamagnetic Co−Fe−B Nanodots
复制标题
超顺磁 Co-Fe-B 纳米点的磁阻动力学
DOI：
10.1103/physrevapplied.13.014063
复制
发表时间：
2020
影响因子：
4.6
通讯作者：
Majetich, Sara A.
中科院分区：
文献类型：
--
作者：
Parks, Brad;Abdelgawad, Ahmed;Wong, Thomas;Evans, Richard F.L.;Majetich, Sara A.
单个盘形纳米点被自旋转移矩驱动进入超顺磁状态，并且它们随时间变化的磁阻波动被测量为电流的函数。边缘处的薄薄一层氧化层对磁化动力学具有显着影响。实验结果和原子自旋模拟相结合表明，钉扎到氧化物颗粒可以降低波动导致反转的可能性，甚至可以改变易轴方向。即使在室温下短暂暴露于小磁场后，也可以观察到交换偏压环路变化和训练效果。该结果对核壳纳米颗粒、小型磁隧道结和自旋扭矩振荡器的研究具有重要意义。
Individual disk-shapednanodots are driven into a superparamagnetic state by a spin-transfer torque, and their time-dependent magnetoresistance fluctuations are measured as a function of current. A thin layer of oxidation at the edges has a dramatic effect on the magnetization dynamics. A combination of experimental results and atomistic spin simulations shows that pinning to oxide grains can reduce the likelihood that fluctuations lead to reversal, and can even change the easy-axis direction. Exchange-bias loop shifts and training effects are observed even at room temperature after brief exposure to small fields. The results have implications for studies of core-shell nanoparticles and small magnetic tunnel junctions and spin-torque oscillators.