Spin-orbit torques from non-epitaxial chalcogenides

Tian-Yue Chen¹, Cheng-Wei Peng¹, Tsung-Yu Tsai¹, Wei-Bang Liao¹, Chun-Te Wu¹, Hung-Wei Yen¹, Chi-Feng Pai^1*

¹Materials Science and Engineering, National Taiwan University, Taipei, Taiwan

* Presenter:Chi-Feng Pai, email:cfpai@ntu.edu.tw

The spin-orbit torques (SOTs) generated from topological insulators (TIs) have gained increasing attention in recent years. These TIs, which are typically formed by epitaxially grown chalcogenides, possess extremely high SOT efficiencies and have great potential to be employed in the next-generation spintronics devices. However, epitaxy of these chalcogenides is required to ensure the existence of topologically-protected
surface state (TSS), which limits the feasibility of using these materials in industry. In this presentation, I will show that non-epitaxial chalcogenide/ferromagnet heterostructures prepared by conventional magnetron sputtering can possess giant SOT efficiencies even without TSS. Through various types of characterization techniques, we find that the damping-like SOT efficiencies originated from the bulk spin-orbit interactions of such non-epitaxial heterostructures can reach values greater than 100% at room temperature. We further demonstrate current-induced SOT switching in these chalcogenide-based heterostructures, which indicates that such non-epitaxial chalcogenide materials can be potential efficient SOT sources in future SOT magnetic memory devices.

Keywords: spintronics, spin Hall effect, spin-orbit torque, chalcogenide , topological inslator