The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties

Abstract

Background: The nanocrystalline structure of La 1-x Ca x FeO 3 was prepared by a sol-gel method involving an autocombustion 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.

Structural, magnetic, and dielectric properties of solution combustion synthesized LaFeO3, LaFe0.9Mn0.1O3, and LaMnO3 perovskites

“…In this regard, it must be mentioned that different parameters such as preparation method, 17 thermal treatment, 17,20,21 crystallite size, 18 morphology, 21 nature of doped cation, [12][13][14][15][16]22 and dopant concentration, 16,22 etc. have a significant impact on the magnetic [16][17][18][20][21][22][23][24][25] and dielectric 21 properties of LaFeO 3 -based materials. In this sense, preparation methods and their parameters have a notable effect on the properties of LaFeO 3 nanoparticles.…”

“…22 Lin and coauthors have studied the effect of Ca substitution on the magnetic properties of LaFeO 3 . 23 Wei et al have demonstrated the higher magnetic and photocatalytic properties of Mn-doped LaFeO 3 compared to LaFeO 3 . 24 Ce doping has been observed to enhance the magnetic properties of LaFeO 3 in comparison with undoped LaFeO 3 and solution combustion synthesis has been found to be a more effective preparation process as compared to the coprecipitation method, and it has a better impact on the physicochemical properties of Ce-doped LaFeO 3 .…”

“…Undoped and doped LaFeO 3 have been prepared by various routes such as sol-gel, 17,23 hydrothermal, 17,21 polymerized complex, 18,22 co-precipitation, 25 electrospinning, 20 solution combustion synthesis, [12][13][14][15]24,25,27 Pechini, 16 and microwave synthesis. 17 Among these synthesis routes, solution combustion synthesis (SCS) has drawn considerable recognition for its simple nature, cost-effectiveness, energy-and time-saving feature, and production of pure homogeneous nano-sized solid materials.…”

Structural and Electrical Properties of Ca2+ Doped LaFeO3: The Effect of A-site Cation Size Mismatch

“…LaFeO 3 is a semiconductor/insulator perovskite oxide and its derived compounds by replacement of some of La atoms by other Re or alkaline earth (Ae) elements give rise to significant physical and chemical properties with promising applications in advanced technologies as in electronics, magnetics, fuel cells, gas sensors, and catalysts [1]. By partially exchanging La in the parent compound with other Re or Ae (La 1-x A x FeO 3 , A: Re or Ae) lead to structurally distorted compounds, and induce different lattice parameters and unit cell volumes [2][3][4]. In addition, Ae doping has an influence on particle size (PS) and grain size (R G ).…”

“…Oxygen deficiency leads to decrease the number of Fe 4+ , and excess oxygen leads to increase the number of Fe 4+ . Furthermore, doping at La site and O vacancy, have a direct impact on the local environment of Fe ions [4] and thereby resistivity. In addition, the difference of ionic radii of La-site ions in the compound and the difference of ionic radii of Fe +3 and Fe +4 have an influence on lattice and electrical properties.…”