Spintronik

Spintronics, or spintronik in some languages, is a branch of electronics that studies electron spin in addition to charge and uses spin states to store and manipulate information. Spin polarization, spin currents, and magnetic moments enable non-volatile memory, reconfigurable logic, and sensitive magnetic sensing. The field integrates condensed matter physics, materials science, and electrical engineering.

Key physical concepts include magnetoresistance, spin injection, spin relaxation, and spin-orbit coupling. The discovery of giant magnetoresistance in 1988 demonstrated that electron spins could influence electrical resistance across multilayer structures, revolutionizing data storage. Later, magnetic tunnel junctions and spin-transfer torque enabled new device concepts such as spin valves and MRAM. Spin-orbit effects, including the spin Hall effect and Rashba effect, allow conversion between charge and spin currents without ferromagnetic materials.

Common materials include ferromagnetic metals (iron, cobalt, nickel) and their alloys, Heusler compounds, magnetic semiconductors, and, more recently, topological insulators and two-dimensional materials. Device concepts include spin valves, magnetic tunnel junctions, spin transistors, and spin-based light sources. MRAM variants—particularly STT-MRAM and SOT-MRAM—are the leading commercial technology for non-volatile memory.

Applications span data storage, magnetic sensing, and potentially quantum information processing. Challenges include achieving efficient spin injection and detection at room temperature, maintaining spin coherence, and integrating spintronic devices with mainstream CMOS processes. Ongoing research aims to expand materials, reduce power, and explore quantum spin-based computing and spin-based neuromorphic approaches.