Determination of spin torque efficiencies in heterostructures with perpendicular magnetic anisotropy
Determination of spin torque efficiencies in heterostructures with perpendicular magnetic anisotropy
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DOI：
10.1103/physrevb.93.144409
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发表时间：
2016-04-08
影响因子：
3.7
通讯作者：
Beach, Geoffrey S. D.
中科院分区：
文献类型：
--
作者：
Pai, Chi-Feng;Mann, Maxwell;Beach, Geoffrey S. D.
我们报告说，通过测量电流感应磁滞回线位移与面内偏置磁场的关系，可以估计具有垂直磁各向异性的 Pt 和 Ta 基磁性异质结构的每电流密度 chi（SHE）的电流感应有效场（SHE）的自旋霍尔效应（SHE）贡献。我们将该技术应用于其铁磁 (FM) 层楔形沉积的 Pt 基样品，并发现由于沉积的 FM 层的不对称性质而产生额外的有效场贡献 chi(Wedged)。我们通过磁光克尔显微镜证实了磁化切换期间 FM 层中的 chi(Wedged) 与不对称脱钉过程之间的相关性。这些结果表明通过控制材料生长过程中域扩展的对称性来设计确定性自旋轨道扭矩切换的可能性。
We report that by measuring a current-induced hysteresis loop shift versus in-plane bias magnetic field, the spin-Hall effect (SHE) contribution of the current-induced effective field per current density chi(SHE) can be estimated for Pt- and Ta-based magnetic heterostructures with perpendicular magnetic anisotropy. We apply this technique to a Pt-based sample with its ferromagnetic (FM) layer being wedged deposited and discover an extra effective field contribution chi(Wedged) due to the asymmetric nature of the deposited FM layer. We confirm the correlation between chi(Wedged) and the asymmetric depinning process in FM layer during magnetization switching by magneto-optical Kerr microscopy. These results indicate the possibility of engineering deterministic spin-orbit torque switching by controlling the symmetry of domain expansion through the materials growth process.