Spintronikka

Spintronikka is a field of electronics and materials science that studies the use of electron spin, in addition to charge, for information processing and storage. Unlike conventional electronics, which rely solely on electron flow, spintronikka explores how spin orientation can encode data, be manipulated by magnetic fields and spin-orbit interactions, and transported through materials with minimal charge movement.

Key concepts include spin polarization, spin currents, and spin relaxation times. Spin transport can occur with or without net charge flow, enabling concepts such as pure spin currents and spin injection across interfaces. Materials of interest include ferromagnetic metals, dilute magnetic semiconductors, and two-dimensional compounds with strong spin-orbit coupling. Common device structures include magnetic tunnel junctions and spin valves, which form the basis of magnetoresistive memories, notably MRAM, and various sensors.

Applications cover non-volatile memory, low-power logic, high-sensitivity magnetic sensing, and prospective quantum information devices. Research targets reducing switching energy, increasing spin coherence, and achieving room-temperature operation compatible with silicon technology. Challenges include interface quality, spin scattering, material imperfections, and scalable fabrication processes. Integration with existing complementary metal-oxide-semiconductor (CMOS) circuits remains a central hurdle.

History and development: the field benefitted from discoveries like giant magnetoresistance and tunneling magnetoresistance in the late 20th century, and has since expanded into industrial memory products and research on spin-based logic and quantum systems.

See also: spintronics, magnetoresistance, MRAM, spin-orbitronics, quantum information.