Electrical, magnetic and magnetocaloric properties of polycrystalline Pr0.63A0.07Sr0.3MnO3 (A=Pr, Sm and Bi)

We studied the effects of the partial substitution (10%) of praseodymium by samarium and bismuth, on the structural, magnetic, magnetocaloric and electrical properties of the Pr(0.63)A(0.07)Sr(0.3)MnO(3) (A=Pr, Sm and Bi) manganites prepared using the solid state reaction. Refinement of the X-ray diffraction patterns shows that all our samples are single phase and crystallize in the orthorhombic structure with Pnma space group. Magnetic studies indicate that all the samples exhibit a ferromagnetic-paramagnetic transition with increasing temperature. Curie temperature T-C decreases by substitution. M(H) curves indicate the presence of some antiferromagnetic domains in the substituted samples testifying the phase-separated nature of these samples. The magnetic entropy curves -Delta S(T) show a maximum in vicinity of Tc. Important values of maximum of -Delta S are recorded for our compounds. For the parent compound, we found 4.59 J/kg K for an applied magnetic field of 2 T at T-C=266 K which raises the possibility of using this compound as a magnetic refrigerant. The temperature dependence of the electrical resistivity rho(7) indicates that all compounds exhibit a metal-insulator transition with increasing temperature. Electrical study suggests the presence of a correlation between electrical and magnetic properties. (C) 2016 Elsevier Ltd. All rights reserved.