LAUSR

Abstract The effects of the substitution of La 3+ by smaller rare-earth ion Pr 3+ on the structural, magnetic and magnetocaloric properties of (La 1- x Pr x ) 0.67 Pb 0.33 MnO 3 (0.0 ≤  x  ≤ 0.3) compounds prepared by sol-gel method have been investigated. X-ray diffraction (XRD) showed that samples crystallize in the orthorhombic perovskite structure with Pnma space group. Thermomagnetic measurements indicate that all the samples exhibit a magnetic transition from ferromagnetic to paramagnetic phase with increasing temperature. Curie temperature, T C , systematically decreases from 358 K for x  = 0.0 to 330 K for x  = 0.3 as the average ionic radius of the A-site elements. The magnetic entropy change, Δ S M , was calculated from the isothermal magnetization measurements as a function of applied magnetic field at several temperatures around T C . The maximum of magnetic entropy change was found to be 4.43, 3.08, 3.33 and 2.97 Jkg −1 K −1 for x  = 0.0, 0.1, 0.2 and 0.3, respectively, for a magnetic field change of 4.8 T. The field dependence of the magnetic entropy change is also analyzed and can be expressed by a power law Δ S m m a x = a ( μ 0 H ) n , where the magnetic-ordering parameter is n  = 0.59, 0.62, 0.62 and 0.65 at 4.8T applied magnetic field for x  = 0.0, 0.1, 0.2 and 0.3 samples, respectively. Arrott plots and universal behavior of the scaled entropy change curves show that all samples display a second order magnetic phase transition.