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

BACKGROUND

The nanocrystalline structure of LaCa FeO was prepared by a sol-gel method involving an auto-combustion process. The incorporation of rare-earths in LaFeO 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 ion doping agent and the calcination temperature on the microstructure, particle morphology, and magnetic properties of LaFeO 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 perovskite did not change even when it was doped with Ca ions, and its space group continued to be Pnma (No.62). FT-IR spectra confirmed that the main band appearing at 568 cm is due to the antisymmetric stretching vibration of Fe-O-Fe bonds in FeO. The introduction of Ca inhibits the growth of grains but the morphology of particles is improved. With an increasing concentration of Ca 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 LaCa FeO tilts towards G-type antiferromagnetism; the magnetic orientation is achieved from the super exchange interaction of Fe ions with oxygen ions.