Magnetocaloric effect and magnetic refrigeration in La_0.7Ca_0.15Sr_0.15Mn_1-xGa_xO₃(0 ≤x≤ 0.1)

Abstract

In this paper we report magnetic and magnetocaloric effect (MCE) properties for La0.7 (CaSr)0.3Mn1-xGaxO3 (x =0, 0.025, 0.05, 0.075 and 0.1) manganites. Our compounds were prepared by sol-gel method and characterized by X-ray diffraction and magnetization measurements. The temperature dependence of the magnetization M(T) reveals a decrease of M with increasing Ga content. The same behavior was observed for the Curie temperature TC. MCE was calculated according to the Maxwell relation based on magnetic measurements. The magnetic entropy change (∆SM) reaches a maximum value witch decreases with increasing Ga content. It is found to decrease from 5.15 J/kgK for x = 0 to 1.86 J/kgK for x = 0.1 under an applied magnetic field of 5T. So, the studied samples could be considered as good materials for magnetic refrigeration for a large temperature interval near room temperature.