The magnetic entropy change in CoMnSb alloys with different crystal sizes

The magnetocaloric effect (MCE) in CoMnSb has been investigated by comparing two samples with different crystal size. One sample is the ingot with crystal size of 120 nm, referred as sample A. The other with average crystal size of 30 nm has been fabricated by rapid solidification method, referred as sample B. It has been found that crystal size dramatically affects the magnetic properties and MCE for CoMnSb alloy. For example, in comparison with sample A, sample B exhibits a lower magnetization and Curie temperature, but an enhanced refrigerant capacity and broader working temperature range. These facts indicate that sample B is superior to the ingot in practical application. The above results are explained in terms of the effect of crystal size and atomic disorder on the intrinsic magnetic properties and magnetic entropy change.