spintronikk

Spintronikk, or spintronics in English, is a field of electronics that studies and utilizes the intrinsic spin of electrons in addition to their charge to store, process, and transmit information. It aims to exploit spin polarization and spin-dependent transport to create devices with nonvolatile memory, higher speed, and lower power consumption.

The field relies on phenomena such as giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR), where the electrical resistance of layered magnetic structures depends on the relative orientation of magnetization in ferromagnetic layers. Spin currents, spin accumulation, and spin relaxation determine how spin information propagates in materials. Efficient spin injection and detection often involve ferromagnetic metals, semiconductors, or novel materials such as Heusler alloys and topological insulators. Spin–orbit effects enable switching via spin-orbit torques.

Common devices include spin valves and magnetic tunnel junctions used in read heads and magnetic random-access memory (MRAM). Spin-transfer torque (STT) and spin–orbit torque (SOT) provide means to write information by reorienting magnetization. Materials research focuses on compatibility with CMOS, thermal stability, and long spin lifetimes.

Applications span nonvolatile memory, magnetic sensing, and advanced logic, with potential for quantum information processing and neuromorphic computing. Major milestones include the discovery of GMR in 1988 and the development of MRAM prototypes in the late 1990s; ongoing work aims to improve scalability, efficiency, and integration.