Magnetic properties and magnetocaloric effects in Mn1.2Fe0.8P1-xGex compounds

We have studied the magnetic properties and magnetocaloric effects in the Mn1.2Fe0.8P1?xGex compounds with x = 0.2, 0.22, 0.3, 0.4 and 0.5. X-ray diffraction patterns show that the Mn1.2Fe0.8P1?xGex compounds crystallize in the hexagonal Fe2P-type crystal structure. The magnetic moments of the Mn1.2Fe0.8P1?xGex compounds measured at 5?K and 5?T increase with increasing Ge content. The Curie temperature increases strongly and the magnetic entropy change has a maximum around 233?K for the compound with x = 0.22, which is about 19 and 31?J?kg?1?K?1 for a field change of 2 and 5?T, respectively.