Spontaneous Vortex Phase Discovered?

Abstract

It is argued that a spontaneous vortex phase probably exists in the recently discovered compound ${\mathrm{ErNi}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ at temperatures below 2.3 K. The consequences of this proposal are discussed. In particular, the magnetic response of the system is studied both above and below 2.3 K, and further experiments are proposed.