Structural, magnetic and electrical study of polycrystalline Pr0.55Sr0.45−xKxMnO3 (x=0, 0.05 and 0.1)

We have investigated the effect of potassium doping on the crystallographic, magnetic, magnetocaloric and electrical properties of Pr0.55Sr0.45−xKxMnO3 with x=0, 0.05 and 0.1. Our samples have been elaborated using the solid state reaction at high temperature. Rietveld refinement of the X-ray diffraction patterns shows that all our samples are single phase and crystallize in the orthorhombic structure with Pbnm space group. Magnetization measurements versus temperature in a magnetic applied field of 0.05 T show that all our samples exhibit a paramagnetic–ferromagnetic transition with decreasing temperature and that all the transitions are around room temperature. The value of the Curie temperature TC decreases with increasing potassium content. The maximum of the absolute value of magnetic entropy change in a magnetic applied field change of 5 T increases from 3.33 J/kg K for x=0 to 4.25 J/kg K for x=0.1. The maximum value of relative cooling power recorded at 5 T is about 247.51 J/K for the sample with x=0.05. All the samples exhibit a metallic–semiconductor transition with increasing temperature.