Superconductor spintronics: modeling spin and charge accumulation in out-of-equilibrium NIS junctions subjected to Zeeman magnetic fields

D. Chevallier (1) , M. Trif (2) , C. Dutreix (3, 4) , M. Guigou (4) , C. H. L. Quay (4) , M. Aprili (4) , C. Bena (2, 4)

1 Universiteit Leiden = Leiden University
2 IPHT - Institut de Physique Théorique - UMR CNRS 3681
3 LOMA - Laboratoire Ondes et Matière d'Aquitaine
4 LPS - Laboratoire de Physique des Solides

We study the spin and charge accumulation in a superconductor when a normal-superconductor tunnel junction is subjected to a Zeeman magnetic field and taken out of equilibrium by applying either a DC or AC voltage bias. We focus on a configuration which allows one to measure non-locally the spin-accumulation using a second ferromagnetic electrode. Our main result is that, in the presence of an AC bias, the time average of the detected non-local signal is frequency dependent, and the frequency at which the saturation occurs is directly related to the inverse of the spin-relaxation time. For a DC bias we also address the effect of the spin accumulation in the normal leads and we investigate the out-of-equilibrium spin susceptibility of the SC, which we show to deviate drastically from its equilibrium value.

Mots clés: spin accumulation in superconductors; out of equilibrium normal-superconductor tunnel junction subjected to Zeeman field; spintronics; spin accumulation in superconductors

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

D. Chevallier, M. Trif, C. Dutreix, M. Guigou, C. H. L. Quay, et al.. Superconductor spintronics: modeling spin and charge accumulation in out-of-equilibrium NIS junctions subjected to Zeeman magnetic fields. New Journal of Physics, 2018, 20, pp.013014. ⟨10.1088/1367-2630/aa9cc7⟩. ⟨hal-01716101⟩