Bias current dependence of superconducting transition temperature in superconducting spin-valve nanowires

Alejandro A. Jara, Evan Moen, Oriol T. Valls, Ilya N. Krivorotov

Research output: Contribution to journalArticle

Abstract

Competition between superconducting and ferromagnetic ordering at interfaces between ferromagnets (F) and superconductors (S) gives rise to several proximity effects such as odd-triplet superconductivity and spin-polarized supercurrents. A prominent example of an S/F proximity effect is the spin switch effect (SSE) observed in S/F/N/F superconducting spin-valve multilayers, in which the superconducting transition temperature Tc is controlled by the angle φ between the magnetic moments of the F layers separated by a nonmagnetic metallic spacer N. Here we present an experimental study of SSE in Nb/Co/Cu/Co/CoOx nanowires measured as a function of bias current flowing in the plane of the layers. These measurements reveal an unexpected dependence of Tc(φ) on the bias current: Tc(π)-Tc(0) changes sign with increasing current bias. We attribute the origin of this bias dependence of the SSE to a spin Hall current flowing perpendicular to the plane of the multilayer, which suppresses Tc of the multilayer. The bias dependence of SSE can be important for hybrid F/S devices such as those used in cryogenic memory for superconducting computers as device dimensions are scaled down to the nanometer length scale.

Original languageEnglish (US)
Article number184512
JournalPhysical Review B
Volume100
Issue number18
DOIs
StatePublished - Nov 25 2019

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