Half-metallic compensated ferrimagnetism in the Mn-Co-V-Al Heusler alloys

Abstract

Abstract Detailed theoretical and experimental investigations on the electronic and magnetic properties of the Mn2Co1−xVxAl Heusler compounds are presented. The magnetization vs. temperature measurements on the Mn2Co1−xVxAl Heusler compounds show a decrease of the Curie temperature with V content, between 745 K (x = 0) and 671 K (x = 0.5). Ferrimagnetic near fully compensated behaviour with the saturation magnetization of 0.29 μB/f.u. has been obtained experimentally for Mn2Co0.5V0.5Al alloy, in slight disagreement with Slater-Pauling rule. The electronic band structure calculations performed using the Korringa-Kohn-Rostoker (KKR) Green’s function method for the Mn2Co0.5V0.5Al alloy show half-metallic almost compensated ferrimagnetic behaviour with total spin moment of 0.02 μB/f.u.. Accounting for the preferential site occupation determined by total energy calculations results an increase of the calculated spin moment, in agreement with the magnetic measurements. The fully compensated ferrimagnetic behaviour is predicted theoretically for the compounds derived from Mn2Co0.5V0.5Al by slight variation on composition. The half-metallic character deduced from density of states (DOS) calculations is expected to be preserved for the stoichiometric and off-stoichiometric alloys.