Özet:
The Pr(Sr1-xPbx)Mn2O6 (0.4 x 0.6) double-perovskite manganite samples have been produced by using a sol-gel method. The Rietveld refinement method has been used to analyse the structural properties, and the results show that all samples are crystallized in monoclinic structure with P21/n space group without any impurity phase. The temperature dependence of magnetization measurement shows that samples exhibit paramagnetic to ferromagnetic phase transition by decreasing temperature. The values of the TC are determined as 286, 280 and 278 K for x= 0.4, 0.5 and 0.6 in Pr(Sr1-xPbx)Mn2O6 samples, respectively. Isothermal applied magnetic field-dependent magnetization curves are used to determine both order of magnetic phase transition and magnetic entropy change (S-M) value. -S-M values are found as 3.68, 3.15 and 2.85 J kg(-1) K-1 for PSPM-4, PSPM-5 and PSPM-6 samples, respectively. Additionally, magnetic phase transition of the samples is identified as second-order magnetic phase transition that indicates accompanying small thermal and magnetic hysteresis to the samples during the phase transition. Relative cooling power (RCP) values are determined as 282, 233 and 268 J kg(-1) for PSPM-4, PSPM-5 and PSPM-6 samples, respectively.
