MAGNETIC PHASE TRANSITION AND MAGNETIC ENTROPY CHANGE OF Gd{sub}5Si{sub}(2-X)Ge{sub}(2-X)Sn{sub}(2X) ALLOYS

摘要

Gd{sub}5Si{sub}(2-x)Ge{sub}(2-x)Sn{sub}(2x)(x=0.05, 0.1, 0.15, 0.2, 0.25, 0.5) were prepared by arc-melting method and the magnetic properties were investigated by a vibrating sample magnetometer. The magnetizations of the Gd{sub}5Si{sub}1.8Ge{sub}1.8Sn{sub}0.4 and Gd{sub}5Si{sub}1.75Ge{sub}1.75Sn{sub}0.5 alloys change abruptly around their Curie temperatures and possess the typical first order phase transition. The magnetic entropy change of the Gd{sub}5Si{sub}(2-x)Ge{sub}(2-x)Sn{sub}(2x) alloys gradually increases with the increase of Sn content. The Gd{sub}5Si{sub}1.75Ge{sub}1.75Sn{sub}0.5 alloy has Gd{sub}5Si{sub}2Ge{sub}2-type monoclinic structure at room temperature, and the maximal magnetic entropy change of this alloy is as large as 16.7J/kg K under a 0～1.8T magnetic field change and at its Curie temperature of 269K, which exceeds that of Gd about two times.