Stability of Half-metallic Behavior with Lattice Variation for Fe(2)MnZ (Z = Si, Ge, Sn) Heusler Alloy

The electronic structure and magnetic properties with variation of lattice constant for Fe(2)MnZ (Z = Si, Ge, Sn) Heusler alloys have been studied. Optimized lattice constant are found to be 5.59, 5.69, 6.00 angstrom for Z=Si, Ge and Sn respectively. Total magnetic moments of the alloys are similar to 3 mu(B) as predicted by the Slater Pauling rule and is maintained over a wide range of lattice variation for all three alloys. Half metallic ferromagnetic nature with 100% spin polarization is observed for Fe2MnSi for a lattice range from 5.40-5.70 angstrom. Fe2MnGe and Fe2MnSn show ferromagnetic and metallic natures with more than 90% spin polarization over a wide range of lattice constant. Due to the stability of half metallic character of these alloys with respect to variation in the lattice parameters, they are promising robust materials suitable for spintronics device applications.