Magnetocaloric effect in LaMn 2− xFe xGe 2 at near room temperature

Abstract

LaMn 2− x Fe x Ge 2 ( x = 0.10 , 0.15, 0.20) alloys were prepared by arc-melt method, the crystal structure and magnetic properties have been investigated by XRD and vibrating sample magnetometer, respectively. The arc-melted LaMn 2− x Fe x Ge 2 alloys mainly crystallize in LaMn 2Ge 2 phase with ThCr 2Si 2-type tetragonal structure, the Curie temperature declines gradually from 310.7 K at x = 0.10 to 274.5 K at x = 0.20 with the increase of transition metal Fe content. The magnetic entropy changes of the series alloys, with the field change from 0 to 18 kOe, are obtained based on the magnetization isotherms at different temperature. The maximal magnetic entropy of LaMn 2− x Fe x Ge 2 decreases a little with increasing substitution of Fe for Mn and is about 1.02 J/(kg K) (0–18 kOe) at x = 0.10 .