Magnetic entropy change in melt-spun MnFePGe (invited)

Giant magnetocaloric effect was observed in Mn1.1Fe0.9P1-xGex (x=0.2, 0.24) melt-spun ribbons. The maximum magnetic entropy change vertical bar Delta S-M vertical bar of Mn1.1Fe0.9P0.76Ge0.24 reaches 35.4 J/kg K in a field change from 0 to 5 T at around 317 K. This value is superior to that reported for Mn1.1Fe0.9P0.76Ge0.24 synthesized by mechanical alloying (similar to 30 J/kg K at 306 K). The large magnetocaloric effect results from a more homogenous element distribution related to the very high cooling rate during melt spinning. The excellent magnetocaloric effect properties, the low material cost, and the accelerated aging regime make the melt-spun-type MnFePGe materials an excellent candidate for magnetic refrigerant applications. (C) 2006 American Institute of Physics.