Spintronics-Based Devices to Circuits: Perspectives and challenges

The science of using the electron's spin in electronic devices is popularly known as spintronics. Researchers have been exploring spintronics to achieve nonvolatility, low dynamic power, zero standby power, and high device density. Several novel materials and phenomena have recently been discovered in this field, including the monumental spin-transfer torque (STT) effect. Since then, aggressive research activities have been conducted in both academia and industry in the field of STT-based devices, circuits, and memories. The accomplishments in this field can be revamped to a nonvolatile computing architecture for the future. The purpose of this article is to review the status and prospects of STT-based devices and their circuit implications along with future challenges. Starting with the basic concepts and device physics, advanced applications of STT are discussed. The outlook for cutting-edge technology is provided in terms of novel magnetoresistive devices embodied in the form of magnetic tunnel junctions (MTJs) controlled by the giant spin Hall effect (GSHE ) and an electric field. Moreover, the concepts of all-spin logic (ASL) and MTJ-based logic are discussed. Their circuit implications and associated challenges are also reviewed.