Large magnetic entropy change and low hysteresis loss in the Nd- and Co-doped La(Fe,Si)13 compounds

The effect of Nd and Co substitution on magnetic entropy changes and hysteresis losses has been investigated for the cubic NaZn13-type LaFe13-xSix compounds. Partially replacing La with Nd leads to a decrease of the Curie temperature T-C and an increase of the magnetic entropy change Delta S. Substitution of Co for Fe in La0.7Nd0.3Fe10.5Si1.5 can adjust T-C to around room temperature. A large Delta S of 15 J/Kg K at T-C=280 K for a field change from 0 to 5 T and a small hysteresis loss close to zero near T-C have been obtained in La0.7Nd0.3Fe10.7Co0.8Si1.5. The Co-doped NaZn13-type LaNdFeSi compounds may be a suitable candidate for magnetic refrigerant near room temperature. (C) 2008 American Institute of Physics.