Critical behaviour of Pr0.5-xGdxSr0.5MnO3 (0 ≤ x ≤ 0.1) manganite compounds: Correlation between experimental and theoretical considerations

In this study, we present an investigation of the critical behaviour of Pr0.5-xGdxSr0.5MnO3 (0 <= x <= 0.1) poly-crystalline compounds synthesized by solid-state reaction method. Magnetic measurements performed around the Curie temperature T-c revealed that our compounds exhibit a second order ferromagnetic (FM) to para-magnetic (PM) transition at T-c. The obtained critical exponents are found to be close to the mean-field model, suggesting a long-range magnetic interactions for all samples. Then, the substitution of Pr by Gd does not affect the universality class. The phenomenological model proposed by Hamad is used to simulate not only the FM-PM transition, but also the two magnetic transitions present in these structures. Furthermore, thanks to this model, the magnetic entropy change and the relative cooling power can be predicted.