Koyama Tomohiro, Guan Yicheng, Chiba Daichi
Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan.
Sci Rep. 2017 Apr 11;7(1):790. doi: 10.1038/s41598-017-00962-7.
Manipulation of magnetization using current-induced torque is crucial for magnetic recording devices. Recently, the spin-orbit torque (SOT) that emerges in a ferromagnetic thin film on a heavy metal is focused as a new scheme for magnetization switching in perpendicularly magnetized systems. Since the SOT provides a perpendicular effective field to the system, the formation of a magnetic multiple domain state because of Joule heating is supressed in the magnetization reversal process. This means that high reliable switching is possible using the SOT. Here, by utilizing the SOT induced domain stability, we show that an electrical current directly injected to a perpendicularly magnetized Pt/Co/Pd system can magnetize itself, that is, current-induced magnetization process from multi to single domain state. A quantitative determination of the SOT is performed using the current-induced magnetization curve. The present results are of great importance as another approach to evaluate the SOT effect, as well as a demonstration of domain state switching caused by the SOT.
利用电流感应转矩来操纵磁化对于磁记录设备至关重要。最近，在重金属上的铁磁薄膜中出现的自旋轨道转矩（SOT）作为垂直磁化系统中磁化翻转的一种新方案受到关注。由于SOT为系统提供了一个垂直有效场，在磁化反转过程中，由焦耳热导致的磁性多畴态的形成受到抑制。这意味着使用SOT可以实现高可靠性的开关。在此，通过利用SOT诱导的畴稳定性，我们表明直接注入到垂直磁化的Pt/Co/Pd系统中的电流能够使自身磁化，即从多畴态到单畴态的电流感应磁化过程。利用电流感应磁化曲线对SOT进行了定量测定。本结果作为评估SOT效应的另一种方法以及SOT引起的畴态切换的演示具有重要意义。
