Magnetocaloric Effects in Pr0.6−xErxSr0.4MnO3 (0.0 ≤ x ≤ 0.2) Manganese Oxides
Résumé
The effects of partial substitution of praseodymium by erbium on the structural, magnetic, and magnetocaloric properties of Pr0.6−xErxSr0.4MnO3 (0.0 ≤ x ≤ 0.2) powder samples have been studied. Our polycrystalline compounds were synthesized by the conventional solid state reaction at high temperature. Rietveld refinement of the X-ray diffraction patterns using Fullprof program shows that all our samples are single phase and crystallize in the orthorhombic structure with the Pnma space group. The unit cell volume decreased with increasing the Er amount. Magnetic measurements show that all our samples exhibit a paramagnetic-ferromagnetic transition with decreasing temperature. The Curie temperature TC shifts to lower values with increasing Er content. From the magnetization isotherms at different temperatures, magnetic entropy changes SM and relative cooling power RCP havebeen evaluated. The maximum of the magnetic entropy changes for the Pr0.45Er0.15Sr0.4MnO3 sample is found to be | delta Smax M | = 2.66 J kg−1 K−1 under a magnetic applied field change of 2 T.