Robust half-metallicity and metamagnetism in Fe_{x}Co_{1-x}S_{2}

Abstract

The Fe_{x}Co_{1-x}S_{2} system is predicted, on the basis of density functional calculations, to be a half metal for a large range of concentrations. Unlike most known half metals, the half metallicity in this system should be very stable with respect to crystallographic disorder and other types of defects. The endmember of the series, CoS_{2}, is not a half metal, but exhibits interesting and unusual magnetic properties which can, however, be reasonably well understood within the density functional theory, particularly with the help of the extended Stoner model. Calculations suggest strong electron-phonon and electron-magnon coupling in the system, and probably a bad metal behavior at high temperatures.