Crystal And Magnetic Structure O Antiferromagnetic Mn2ptpd

We have investigated the crystal and magnetic structure of Mn2PtPd alloy using powder x-ray and neutron diffraction experiments. This compound is believed to belong to the Hensler family having crystal symmetry I4/mmm (TiAl3-type). however, in this work we found that the Pd and Pt atoms are disordered and thus Mn2PtPd crystallizes in the L1(0) structure having P4/mmm symmetry (CuAu-I type) like MnPt and MnPd binary alloys. The lattice constants are a = 2.86 angstrom and c = 3.62 angstrom at room temperature. Mn2PtPd has a collinear antiferromagnetic spin structure below the Neel temperature T-N = 866 K, where Mn moments of similar to 4 mu B lie in the ab-plane. We observed a strong change in the lattice parameters near TN. The sample exhibits metallic behaviour, where electrical resistivity and carrier concentration are of the order of 10(-5) Omega cm and 10(21) cm(-3), respectively.