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

The magnetic and magnetocaloric properties of Mn(1.1)Fe(0.9)p(1-x)Ge(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 Mn1.1Fe0.9P1-xGex 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.