Structural and magnetic properties of (La0.70−xYx)Ba0.30Mn1−xFexO3 perovskites simultaneously doped on A and B sites (0.0 ≤ x ≤ 0.30)
Résumé
We present the structural and magnetic properties of polycrystalline samples of the solid solution (La0.70−xYx)Ba0.30Mn1−xFexO3 (x = 0.00, 0.10, 0.20 and 0.30). Samples have been prepared by a conventional solid-state reaction method in air. Rietveld refinements of the X-ray powder diffraction data show a structural transition from rhombohedral (View the MathML sourceR3¯c) to orthorhombic (Pbnm) symmetry when x ≥ 0.10. The ZFC, FC and M(H) measurements lead to conclude that the samples with x ≥ 0.10 behave like spin-glass systems. The substitution of Mn3+ ions by Fe3+ ions triggers antiferromagnetic interactions between the Fe3+ and Mn4+ spins. The values of the magnetization (M(H)) decrease when increasing the Fe content. On the basis of a simple model of Mn and Fe spins pointing in opposite directions, we found the experimental data close to the calculated values, confirming the antiferromagnetic alignment between Fe and Mn moments.