Effect of praseodymium doping on the structural, magnetic and magnetocaloric properties of Sm0.55Sr0.45MnO3 manganite

The effect of praseodymium doping on the microstructure, magnetic and magnetocaloric effects in Sm0.55−xPrxSr0.45MnO3 (x=0.0 and x=0.1) has been investigated. Our compounds have been elaborated using the conventional solid-state reaction at high temperature. X-Ray diffraction study reveals that our samples crystallize in the distorted orthorhombic system with Pbnm space group. Magnetization measurements M (T) at H=0.05T were performed and show a paramagnetic (PM) to ferromagnetic (FM) transition with decreasing temperature. Praseodymium doping leads to an increase of the Curie temperature TC from 95K (x=0.0) to 132K (x=0.1). Moreover, we observe a small anomaly in the M (T) behavior around 30K. It has been shown that x=0.1 sample exhibit first order FM–PM phase transition under low magnetic field accompanied by a thermal hysteresis in the field cooled cooling and warming protocols. However, the phase transition from PM to FM is modified from first order to second order above a critical field HC. A metamagnetic behavior has been observed in the M (H) curves around 110K for x=0.0 and 160K for x=0.1. The maximum of the magnetic entropy change (−ΔSMmax) was calculated using the isothermal magnetization curves M (H) under magnetic field change of 5T and is found to be 6.56Jkg−1K−1 for x=0.0 and 7.14Jkg−1K−1 for x=0.1. The relative cooling power (RCP) is found to be 222.6J/Kg and 258.8J/Kg for x=0.0 and x=0.1, respectively. This suggests that these compounds may be suitable candidates for magnetic refrigeration. •Pr-doped Sm0.55Sr0.45MnO3 are synthesized using the ceramic method at high temperatures.•Pr-doping increases TC from 95K (x=0.0) to 132K (x=0.1).•A critical field HC induced phase transition from FOMT to SOMT.