Specific features of the properties of half-metallic ferromagnetic Heusler alloys Fe2MnAl, Fe2MnSi, and Co2MnAl

Abstract

The structural, magnetic, and electrical properties of half-metallic Heusler alloys Fe2MnAl, Fe2MnSi, and Co2MnAl have been investigated in the temperature range of 4–900 K. According to the X-ray diffraction analysis, these alloys have the B2 and L21 structures with different degrees of atomic order. The magnetic state of the alloys is considered as a two-sublattice ferrimagnet. The electrical resistivity and thermoelectric power have been discussed in the framework of the two-current conduction model taking into account the existence of an energy gap in the electronic spectrum of the alloys near the Fermi level for the subband with spin-down (minority) electrons.