Influence of the substitution of Cu for Si on magnetic entropy change and hysteresis loss in LaFe11.7(Si1-xCux)1.3 compounds

The magnetic properties, magnetic entropy change, and hysteresis loss in LaFe11.7(Si1-xCux)(1.3) compounds were investigated. It was found that the compounds retain the cubic NaZn13 structure when the substitution of Cu reaches 20%. With increasing Cu content from x=0 to 0.2, the Curie temperature T-C increases from 185 to 200 K, while lattice parameter decreases from 11.475 to 11.468 due to the smaller atomic radius of Cu than Si. Metamagnetic behavior becomes weaker and magnetic entropy change vertical bar Delta S vertical bar drops with raising Cu content. However, vertical bar Delta S vertical bar still remains a large value, similar to 20 J/kg K, when x reaches 0.2. An attractive feature is that both thermal and magnetic hysteresis can be remarkably reduced by introducing Cu. The maximum hysteresis loss at T-C drops from 74.1 to 0 J/kg when the substitution of Cu for Si increases from 0% to 20%. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3063067]