Spin injection, diffusion, and detection in lateral spin-valves

Abstract

We demonstrate the injection of spin-polarized electrons into paramagnetic Au nanowires by driving an electric current from a ferromagnetic permalloy (Py) electrode. The nonequilibrium spin accumulation in Au results in a difference between the chemical potentials for spin-up and spin-down electrons that is detected as a field-dependent voltage signal using a second Py electrode. The magnitude of the voltage contrast (>10%) and its coincidence with the magnetic switching of the Py electrodes attest to the spin-sensitive origin of the signals. By increasing the separation of the Py injector and detector, we observe an exponential decay of the spin signals. The measurements yield a spin-diffusion length of 63±15nm and an injected spin polarization of 3% in Au at 10 K.

Circularly polarized luminescence microscopy for the imaging of charge and spin diffusion in semiconductors

“…In centro-symmetric materials where the spin-orbit interaction is weak (and thus  s long) such as silicon, much larger room temperature spin drift and diffusion lengths are obtained. 8 Apart from non local spin accumulation experiments requiring several samples with electrical contacts spaced by different lengths, 9 L s (but not L) is typically measured using spatially resolved Faraday or Kerr rotation (also known as Kerr microscopy). 10 When combined with time resolution, a direct measure of D s = L s 2 / s is possible.…”

Kondo physics in non-local metallic spin transport devices

“…This non-local geometry has enabled significant advances in the understanding of spin transport in metals [4][5][6][7][8][9][10][11][12][13][14][15][16]18,22,[24][25][26][27][28][29][30][31][32][33][34][35][36][37] , but has also highlighted serious discrepancies with theory. The primary example of the latter is the surprising non-monotonicity in the temperature (T) dependence of DR NL , and thus the deduced l N , in the transparent interface limit.…”

“…Surface spin relaxation 10 , reduced dimensions 9 and surface 18 / bulk 8 (magnetic) impurities have all been advanced, but no consensus has emerged. One issue contributing to this is the focus on only a small set of materials, with Ni 80 Fe 20 /Cu and Ni 80 Fe 20 / Ag accounting for a major fraction of prior work 10,18,28,[30][31][32][33][34][35]39 .…”

Spin relaxation through Kondo scattering in Cu/Py lateral spin valves

“…The structure has been successfully used to measure spin transport through various metallic [6][7][8] and semiconducting [9,10] materials. LSVs consist of two ferromagnetic (FM) electrodes bridged by a nonmagnetic (NM) nanowire.…”