Ionic radii correlative study on LaFe0.5Cr0.5O3 and YbFe0.5Cr0.5O3magnetic double perovskites

Comparative study on the iso-structural compounds LaFe0.5Cr0.5O3 (LFCO) and YbFe0.5Cr0.5O3 (YFCO) are carried out to investigate the structural, optical and magnetic properties. Rietveld refinement and the derived structural parameters disclose the extent of distortion exhibited by the ions substituted in the orthorhombic lattice. Raman analysis describes the genuine differences in the phonon modes. Contradictory Raman shift observed in the oxygen breathing mode at ~679 cm−1 denotes the existence of the multi-valence state in LFCO than YFCO. EPR and XPS analysis validates the multi-valence state of Cr3+/4+/6 ions present in the LFCO compound. The optical transition between the Cr3+/Fe3+ ions is studied by diffuse reflectance spectroscopy, where the direct bandgap energy (Eg) is 2.05 and 2.08 eV, respectively. Magnetic measurement reveals complex magnetic Phenomena such as magnetisation reversal and spin reorientation transition, illustrating a contrast in the magnetic interaction present due to La3+(non-magnetic) and Yb3+ (magnetic) ion and with the interplay of Cr3+/Fe3+ ion between their sublattices.