The discovery of electron spin by O. Stern and W. Gerlach in 1922 paved the way for advancements in spintronics, a field focused on the electron's spin and its potential for innovative electronic devices. Key breakthroughs include tunneling magnetoresistance and giant magnetoresistance, both of which are spin-dependent phenomena that have revolutionized read heads in magnetic hard disk drives. Recent developments in spintronics feature magnetic racetrack memory, which utilizes spin-torque magnetic domain wall motion, and the all-optical alignment of magnetic domains via the inverse Faraday effect, both promising for future magnetic recording applications. The spin-transistor, proposed in 1990, holds the potential to surpass conventional semiconductor transistors if successfully developed. As spintronics matures, challenges remain, particularly in materials science, where identifying and engineering compounds for efficient spin-polarization and spin-transport is crucial. These materials should ideally integrate seamlessly with existing semiconductor technology. Additionally, real-world prototypes are needed to validate device concepts, while understanding spin-loss mechanisms and optimizing electron spin interactions with their environment are fundamental scientific issues to address. Furthermore, spin-based electronics may play a role in advancing quantum computation schemes.
