Spin superfluidity

TL;DR

This paper explores the theoretical foundations and experimental prospects of spin superfluidity, a phenomenon allowing dissipationless spin transport in magnetic materials with easy-plane topology, despite the lack of strict spin conservation.

Contribution

It analyzes the topology of the order parameter space, the Landau criterion, and decay mechanisms of spin superfluid currents, providing a comprehensive theoretical framework.

Findings

Topological analysis of order parameter space for spin superfluidity

Discussion of Landau criterion applicability to spin transport

Survey of experimental approaches to detect spin superfluidity

Abstract

The phenomenon of superfluidity (superconductivity) is a possibility of transport of mass (charge) on macroscopical distances without essential dissipation. In magnetically ordered media with easy-plane topology of the order parameter space the superfluid transport of spin is also possible despite the absence of the strict conservation law for spin. The article addresses three key issues in the theory of spin superfluidity: topology of the order parameter space, Landau criterion for superfluidity, and decay of superfluid currents via phase slip events, in which magnetic vortices cross current streamlines. Experiments on detection of spin superfluidity are also surveyed.