Spin-polarization and electronic properties of half-metallic Heusler alloys calculated fromfirst principles

Abstract

Half-metallic Heusler alloys are amongst the most promising materials for futuremagneto-electronic applications. We review some recent results on the electronicproperties of these compounds. The origin of the gap in these half-metallic alloysand its connection to the magnetic properties are well understood. Changing thelattice parameter slightly shifts the Fermi level. Spin–orbit coupling induces stateswithin the gap but the alloys keep a very high degree of spin polarization at theFermi level. Small degrees of doping and disorder as well as defects with lowformation energy have little effect on the properties of the gap, while temperatureeffects can lead to a quick loss of half-metallicity. Finally, we discuss two specialissues: the case of quaternary Heusler alloys and the half-metallic ferrimagnets.