Magnetocaloric effect and magnetic refrigeration in La0.7Ca0.15Sr0.15Mn1-xGaxO3 (0 x 0.1)

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 (ΔSM) 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. Keywords. Manganites, Magnetocaloric Effect, Magnetic refrigeration, Relative cooling power.