Spin-orbit torque switching in sputtered BiTe driven by spin Hall effect

Topological insulators (TIs) are the most popular spin-orbit torque (SOT) materials in spintronics society. TIs possess extremely high damping-like (DL) SOT efficiency due to the spin momentum locking from the topological surface state (TSS). However, most works prepared TIs are utilizing the molecular beam epitaxy, which is hard to employ in the industrial fabrication process. Therefore, integrating the industry-favored tool to prepare large SOT materials becomes a crucial issue.
In this work, we use conventional magnetron sputtering to deposit the non-epitaxial BiTe/ferromagnet heterostructures. The harmonic Hall voltage measurement and the hysteresis loop shift measurement are performed to characterize the DL-SOT efficiency. Even without the TSS, the DL-SOT efficiency of the non-epitaxial BiTe can reach values greater than 100% at room temperature. From the thickness dependence analysis, we conclude that the bulk SHE has a great contribution to the SOT [1]. Moreover, the current-induced SOT switching is demonstrated in these BiTe-based devices, which indicates the non-epitaxial chalcogenide materials are the potentially efficient SOT sources in future SOT magnetic memory devices.

[1] T.-Y. Chen, et al. ACS Appl. Mater. & Inter. 12, 7788-7794 (2020).