Realization of a Heusler alloy Mn2FeAl with B2 ordering

The electronic structure and the influence of disorder for Mn2FeAl have been studied by first principles calculations. The ground magnetic structure shows an antiparallel arrangement between two Mn atoms. The spin down band structure shows an indirect gap with a width of about 0.334eV. The result of density of states for different degrees of disorder shows that the disorder could destroy the peak in spin-up states and the gap in spin-down states around Fermi energy. Therefore, the disorder could avoid the Jahn-Teller distortion and stabilize the cubic phase for Mn2FeAl. In experiment, the cubic phase for Mn2FeAl has been epitaxially grown on MgO by molecular beam epitaxy on the MgO substrate. The structural properties have been investigated by x-ray diffraction, which indicates a B2 order of Mn2FeAl. The magnetization and transport properties resulting from the B2 order have been investigated.