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

¹ Faculté des Sciences de Sfax, Université de Sfax, Laboratoire de Physique des matériaux, B. P. 1171, Sfax 3000, Tunisia
² University of Applied Sciences of Western Switzerland, Institute of Thermal Sciences and Engineering, CH-1401 Yverdon-les-Bains, Switzerland

^a e-mail: safa.othmani@gmail.com

Abstract

In this paper we report magnetic and magnetocaloric effect (MCE) properties for La_0.7 (CaSr)_0.3Mn_1-xGa_xO₃ (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 (∆S_M) 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.