Crystal structure and magnetic transition of MnFePGe compound prepared by spark plasma sintering

The crystal structure and magnetic transition were studied for the bulk Mn1.1Fe0.9P0.8Ge0.2 compound prepared by a simple blending and subsequent spark plasma sintering route. X-ray diffraction analysis and refinement show that the compound crystallizes in the hexagonal Fe2P-type structure, in which the Mn atoms occupy all the 3g sites and some 3f sites, the Fe atoms occupy the rest of the 3f sites, and P and the Ge atoms randomly occupy the 2c and 1b sites. Magnetic measurement indicates that the Curie temperature TC is at 253K and the thermal hysteresis of M-T curves at TC upon heating and cooling, a signature of a first-order magnetic phase transition, is about 15K. The maximum magnetic entropy change of the compound reaches as high as 49.2J∕kgK in a field change from 0to5T at 253K, while the adiabatic temperature change of the compound reaches only 1.2K in a field change from 0to1.5T at the same temperature.