The influence of Ca substitution on LaFeO ₃ nanoparticles in terms of structural and magnetic properties

Background: The nanocrystalline structure of La _{1 -x} Ca _x FeO ₃ was prepared by a sol–gel method involving an auto-combustion process. The incorporation of rare-earths in LaFeO ₃ induces strain in magnetic properties, especially in terms of the following parameters: replacement amount, oxygen partial pressure, and calcination temperature. Methods: To determine the effects of the amount of Ca ²⁺ ion doping agent and the calcination temperature on the microstructure, particle morphology, and magnetic properties of LaFeO ₃ crystal, we performed the following respective analytical methods: X-ray powder diffraction, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy, and vibrating sample magnetometer tests. Results: The orthorhombic structure of LaFeO ₃ perovskite did not change even when it was doped with Ca ²⁺ ions, and its space group continued to be Pnma (No.62). FT-IR spectra confirmed that the main band appearing at 568 cm ⁻¹ is due to the antisymmetric stretching vibration of Fe–O–Fe bonds in FeO ₆ . The introduction of Ca inhibits the growth of grains but the morphology of particles is improved. With an increasing concentration of Ca ²⁺ ions, magnetic behavior of the samples also witnessed an increasing trend in a proportionate manner. With an increase in calcination temperature, the enclosed area of the magnetic hysteresis curve of the sample reduced remarkably. Conclusions: The growth of nanoparticles can be restrained with an increase of Ca content that is used as doping agent. The magnetic behavior of La _{1 -x} Ca _x FeO ₃ tilts towards G-type antiferromagnetism; the magnetic orientation is achieved from the super exchange interaction of Fe ³⁺ ions with oxygen ions.