The magnetocaloric effect in Nd(Co_(1-x)Fe_x) _(12)B_6 alloys

摘要

The first-order phase transitions in NdFe_(12)B_6 and PrFe_(12)B_6 alloys give rise to giant values of magnetic entropy changes in relatively low field. However, the metastable nature of these alloys associates with a special procedure of preparation and considerable amount of impurities inevitably. By alloying NdFe_(12)B_6 with the iso-structural compound of NdCo_(12)B_6 appropriately, a Nd(Co_(1-x)Fe_x)_(12)B_6 system which possesses the stable SrNi_(12)B_6-type structure can be obtained directly via the standard casting-and-annealing method. Remarkably improved thermal and magnetic reversibility are observed in the present system. The second-order phase transitions in NdCo_(12)B_6 alloy give rise to the relative cooling power, which is comparable with that of NdFe _(12)B_6 alloy around the ordering temperature.