Evidence for Itinerantd-Electron Ferromagnetism

Abstract

We describe here a metallic ferromagnetic system ${\mathrm{Fe}}_{1-x}{\mathrm{Co}}_x{\mathrm{S}}_2$ and ${\mathrm{Co}}_{1-x}{\mathrm{Ni}}_x{\mathrm{S}}_2$ that appears to have a single doubly degenerate band. The electrons in the band are itinerant as manifested by metallic electrical conductivity, but the magnetic moment is that of the isolated ion.