The influence of rare earth doping on the structure, magnetic properties, and application of LaFeO3 nanoparticles

Abstract

The perovskites La_1-xR_xFeO₃ (x = 0.0 and 0.1; M: Sm³⁺ and Gd³⁺) were synthesized using the citrate method. The X-ray diffraction reveals that the samples were prepared in a single phase orthorhombic structure with an average crystallite size of 42–46 nm. The field emission scanning electron microscope studied the morphology of La_1-xR_xFeO₃ perovskites and indicated the presence of pores on the surface of nanoparticles. The magnetization of LaFeO₃ has a strong effect on the doping La³⁺ site by Sm³⁺ and Gd³⁺ ions. The saturation magnetization increased from 0.57 emu/g for LaFeO₃ to 1.27 emu/g for La_0.90Sm_0.10FeO₃; while, the remnant magnetization decreased from 0.111 emu/g for LaFeO₃ to 0.026 emu/g for La_0.90Gd_0.10FeO₃. The samples have antiferromagnetic with weak ferromagnetic properties. The presence of Sm³⁺ and Gd³⁺ ions at the expense of La³⁺ leads to tilting the FeO₆ octahedron and increasing the canting angle between Fe³⁺ –O₂–Fe³⁺. The La_1-xR_xFeO₃ nanoparticles have a good removal efficiency for removing highly toxic Cr⁶⁺ ions from water using a low-cost and eco-friendly adsorption method. The removal efficiency of La_0.90Gd_0.10FeO₃ is 88.2% at pH 5. The Langmuir model is the best fit model with the experimental data.