Energy Conversion and Energy Harvesting in Spin Diodes

Spin diodes are novel nanoscale spintronic devices capable of converting an input alternating current (AC) signal (signal current) into an output direct current (DC) voltage. Nowadays, ferromagnet-based spin diodes are considered as promising signal detectors for many practical applications, including signal amplitude detection, signal frequency detection, spectrum analysis, and energy harvesting, while the development of antiferromagnet-based spin diodes has started not so long ago. In this chapter, we review the operation principles of ferromagnet- and antiferromagnet-based spin diodes and discuss their features with a focus on the physics of the energy conversion and energy harvesting processes, and also briefly discuss the advances, trends, and problems in the physics and applications of spin diodes.