Magnetic-entropy change in Mn1.1Fe0.9P1-xGex compounds

The magnetic and magnetocaloric properties of Mn_1.1Fe_0.9p_1-xGe_x compounds with x=0.20,0.22,0.23,0.26, and 0.30 have been investigated. In the composition range x from 0.20 to 0.30, the compounds crystallize in the Fe₂P-type hexagonal structure. The Curie temperature of the compounds strongly increases with increasing Ge contents. A history dependence of the magnetic phase transition is observed in this compound system. The optimum composition range and the temperature range of the Mn_1.1 Fe_0.9P_1-xGe_x compounds for magnetic refrigeration applications have been determined. In the composition range x from 0.20 to 0.23, the compounds exhibit large magnetic-entropy change in a low magnetic field.