Curie temperatures of zinc-blende half-metallic ferromagnets

Using density-functional theory in the local-density approximation and spin-fluctuation theory, the Curie temperatures of the zinc-blende half-metallic ferromagnets VAs, CrAs, MnAs and the Heusler compound NiMnSb have been estimated, the lower bounds obtained being ab initio. The orders of magnitude are the same as the Curie temperature of the half-metallic ferromagnet NiMnSb with T_c=701K. Of the three compounds VAs, CrAs, and MnAs, the highest T_c is calculated for CrAs, for which the Fermi energy is in the middle of the minority-spin electron gap; its Curie temperature might be as high as 1000 K. The Curie temperature drops sharply when the Fermi energy moves into the minority-electron conduction band as in the case of MnAs.