Thermally activated phase slips in superfluid spin transport in magnetic wires

Abstract

We theoretically study thermally activated phase slips in superfluid spin transport in easy-plane magnetic wires within the stochastic Landau-Lifshitz-Gilbert phenomenology, which runs parallel to the Langer-Ambegaokar-McCumber-Halperin theory for thermal resistances in superconducting wires. To that end, we start by obtaining the exact solutions for free-energy minima and saddle points. We provide an analytical expression for the phase-slip rate in the zero spin-current limit, which involves a detailed analysis of spin fluctuations at the extrema of the free energy. An experimental setup for a magnetoelectric circuit is proposed, in which thermal phase slips can be inferred by measuring nonlocal magnetoresistance.