Signatures of dynamically polarized nuclear spins in all-electrical lateral spin transport devices

摘要

The effect of nuclear spins in Fe/GaAs all-electrical spin-injection devicesis investigated. At temperatures below 50 K, strong modifications of thenon-local spin signal are found that are characteristic for hyperfine couplingbetween conduction electrons and dynamically polarized nuclear spins. Theperpendicular component of the nuclear Overhauser field depolarizes electronspins near zero in-plane external magnetic field, and can suppress suchdephasing when antialigned with the external field, leading to satellite peaksin a Hanle measurement. The features observed agree well with a Monte Carlosimulation of the spin diffusion equation including hyperfine interaction, andare used to study the nuclear spin dynamics and relate it to the spinpolarization of injected electrons.