Challenges and opportunities for spintronics based on spin orbit torque

Spintronic devices based on spin orbit torque (SOT) have become the most promising pathway to the next-generation of ultralow-power nonvolatile logic and memory applications. Typical SOT-based spintronic devices consist of two functional materials: a spin source and a magnetic material. Spin source materials possess a strong spin orbit coupling, enabling efficient interconversion between charge and spin current. Magnetic materials are used to process and archive the information via the interaction between the local magnetic moment and the spin current generated from spin source. Considerable efforts have been put into the design of materials and devices in the past decades to realize the electrical control of magnetic switching. However, a number of key challenges still remain to be addressed for the practical application. In this paper, we reviewed the development of a range of novel materials for both the spin source and the magnetic functionalities, particularly the complex oxides and organic spintronic materials. We also discussed and highlighted several key issues, such as the mechanism and manipulation of SOT and the large-scale integration of SOT-based devices, which merit more attention in the future.