CoMnSb: A magnetocaloric material with a large low-field magnetic entropy change at intermediate temperature

A large magnetocaloric effect (MCE) has been achieved in a rare-earth-free CoMnSb alloy at low magnetic field and intermediate temperature. It is interesting to note that a relatively large magnetic entropy change vertical bar Delta S-M vertical bar of 2.06 J/kg K with Delta H=0.9 T was obtained around 471 K. Arrott plots at various temperatures reveal that a second order magnetic transformation occurs near the Curie temperature. The origin of the large Delta S-M under the conditions of intermediate temperature and low field is attributed to the magnetic transition from ferromagnetic to paramagnetic. These results suggest that CoMnSb alloy is a good candidate for large MCE when being utilized in intermediate temperature refrigeration systems for some special cases. This investigation demonstrates that some transition metal alloys with large magnetic moments may exhibit large MCE, which extends the region for exploring useful MCE materials. (c) 2006 American Institute of Physics.