Electronic transport that exploits the spin degree of freedom in addition to charge. Foundational: Mott 1936 two-current model of spin-polarised conduction in ferromagnets; Julliere 1975 tunneling-magnetoresistance ratio between parallel…
spintronics
GMR: ρ_AP − ρ_P = 4β²ρ*λ_sf/L-dependent — parallel/antiparallel resistance difference
Baibich-Fert 1988 / Grünberg 1989 GMR (2007 Nobel): Fe/Cr multilayers show a ~50% resistance drop when external field aligns neighbouring…
Spin-transfer torque: J_s > J_c ⇒ precessional switching of free-layer magnetisation
Berger 1996 / Slonczewski 1996 spin-transfer torque: a spin-polarised current passing through a ferromagnetic free layer transfers angular…
Spin-Hall effect: J_c → J_s transverse — intrinsic + skew + side-jump mechanisms
Dyakonov-Perel 1971 / Hirsch 1999 spin-Hall effect: charge current in a material with spin-orbit coupling generates a transverse spin…
Julliere TMR ratio: (R_AP − R_P)/R_P = 2 P₁P₂ / (1 − P₁P₂)
Julliere 1975 tunneling-magnetoresistance ratio for a magnetic tunnel junction (MTJ) with two ferromagnetic electrodes separated by an…
Spin-Hall angle: θ_SH = σ_SH / σ_xx — charge-to-spin-current conversion efficiency
Spin-Hall angle θ_SH is a dimensionless material figure of merit for charge-to-spin-current conversion: θ_SH = σ_SH / σ_xx, i.e. the ratio…
Mott two-current model: ρ_P ~ parallel of (ρ_↑ ∥ ρ_↓), both low; ρ_AP ~ series
Mott 1936 / 1964 two-current model: in a ferromagnet, electrons with spin-majority and spin-minority at E_F scatter through independent…