Magnetic, magnetotransport and critical properties of polycrystalline Pr0.7Sr0.3MnO3 located at the tricritical point

In this work, we present a detailed investigation on the electrical and magnetic effects in a Pr0.7Sr0.3MnO3 ceramic, which was synthesized by a solid state reaction method. The Rietveld refinement analysis suggests that the sample is single phase of Pr0.7Sr0.3MnO3, has an orthorhombic structure with space group of Pbnm. Based on magnetic field and temperature dependences of the magnetization, M(H,T), we have estimated the critical parameters of Pr0.7Sr0.3MnO3 near T-c(beta = 0.20-0.23, gamma= 0.87-1.10, delta = 5.54-6.01, and T-c = 256-258 K), suggesting that its ferromagnetic-paramagnetic phase transition is located at the tricritical point. Our results also suggest that the critical behavior of this material is significantly influenced by the selected magnetic field range and the contribution of the demagnetization field. The magnetocaloric and the magnetoresistance effects associated to the double-exchange interactions in the sample have been investigated via the temperature and magnetic field dependences of the resistivity, rho(T,H), and M(H,T) data. Under an applied field of 10 kOe, the maximum values of the magnetic entropy change (Delta S-m) and the magnetoresistance (MR = 100%x[rho(H)-rho(0)/rho(H)) are found to be about - 3.1 J/kgK and - 123.8%, respectively. The suitability of the value as well as the tendency of Delta S-m(T) determined through the data sets M(H), M(T) and rho(T) shows that these phenomenological models can be completely applied in the study of the thermal effects of materials. Additionally, the low-field magnetoresistance effect, the field dependences of the ordering temperature of Pr and the maximum value of Delta S-m of Pr0.7Sr0.3MnO3 ceramic have also been considered. (C) 2021 Elsevier B.V. All rights reserved.