The influence of spin state of the Cr ions on the structural and magnetic behavior of orthorhombic LaFe1−xCrxO3 Perovskites (0.0<x<0.5)

Abstract Herein, we report, for the first time, the influence of the state of spin of the Cr 3+ ions on the structure and magnetic behavior of LaFe 1−x Cr x O 3 (0.0 < x < 0.5) perovskite crystal structures to improve their magnetic properties for memory storage and magneto-optical application potential. A series of LaFe 1−x Cr x O 3 (0.0 < x < 0.5) nanocrystals was prepared using the citrate-nitrate auto-combustion route. The influence of the Cr 3+ ions on the structure and morphology of the LaFe 1−x Cr x O 3 nanostructures was emphasized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), the selected area of electron diffraction (SAED), and scanning electron microscopy (SEM). The results revealed that the inclusion of the Cr 3+ ions into the Fe 3+ sites leads to an increase in the crystallite size of the LaFe 1−x Cr x O 3 (0.0 < x < 0.5) nanocrystals, from 16.12 to 57.29 nm, to preserve their orthorhombic crystal symmetry. The phase stability and the electron density mapping of the prepared orthoferrite nanocrystals were verified using the Goldschmidt tolerance factor and Rietveld refinement. The magnetic properties were evaluated and discussed based on Kanamori–Goodenough (KG) regulations and Heisenberg Hamiltonian notation. The results showed that the inclusion of the 20 mol% of Cr 3+ ions in the Fe sites results in an enhancement of the magnetic parameters. The enhancement of the magnetic behavior was argued to the tendency of the Cr 3+ ions to be in the high spin state when included in the Fe 3+ ions site. This improvement in the magnetic performance of the LaFe 1−x Cr x O 3 (x = 0.2) nanocrystals will open a new avenue for using this nanomagnetic material in the fields of memory storage and magneto-optical devices.