Abstract
Abstract 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 –Δ S ( T ) show a maximum in vicinity of T C . Important values of maximum of −Δ 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 ρ ( T ) 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.
Published Version
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