Superconductivity and Spin Superfluidity

Abstract

When a magnetic field is applied to a ferromagnetic ring with easy-plane anisotrophy, steady states with circulating spin currents occur. In a similar way, when a magnetic field is applied to a superconducting ring, circulating charge currents will appear. These currents are described by very similar hydrodynamic expressions. When a magnetic field is applied to a superconducting ferromagnet, these hydrodynamic equations become coupled, which leads to different steady states.