Room-temperature perpendicular magnetic anisotropy of Pt/Co/AlOx trilayers on SrTiO3 (001)

We demonstrate room-temperature perpendicular magnetic anisotropy (PMA) in Pt/Co/AlOx trilayers sputter-deposited onto a SrTiO3 (STO) (001) substrate. Reflection high-energy electron diffraction and x-ray diffraction results confirm the two-dimensional polycrystalline nature for both Pt and Co layers in PMA films, which are (111) oriented in the out-of-plane direction. While the PMA in Pt/Co/AlOx trilayers on STO (001) is found to have interfacial origins, sizable PMA is maintained when Pt layer thickness is as thin as 1 nm, which is several times to one order of magnitude smaller than the reported values of the spin diffusion length for Pt, thus facilitating spin transmission along the thin-film-normal direction. With the STO (001) substrate serving as the fundamental building block for realizing giant Rashba spin splitting, this work provides a feasible platform for the investigation of magnetization switching in two-dimensional-electron-gas-based magnetic hetero-structures at room temperature.

我们在溅射沉积到SrTiO₃（STO）（001）衬底上的Pt/Co/AlOx三层膜中展示了室温垂直磁各向异性（PMA）。反射高能电子衍射和X射线衍射结果证实了PMA薄膜中Pt和Co层的二维多晶性质，它们在面外方向上是（111）取向的。虽然发现STO（001）上的Pt/Co/AlOx三层膜中的PMA具有界面起源，但当Pt层厚度薄至1nm时，仍能保持相当大的PMA，这比所报道的Pt的自旋扩散长度值小几倍到一个数量级，从而有利于沿薄膜法线方向的自旋传输。由于STO（001）衬底是实现巨大Rashba自旋劈裂的基本构建块，这项工作为在室温下研究基于二维电子气的磁性异质结构中的磁化翻转提供了一个可行的平台。