Study on crystal structure, electrical and magnetic properties of LaFe xCo1-xO3 prepared by sol-gel method

Abstract

Lanthanum Ferri-cobaltates magnetic semiconducting materials are very interesting materials and they have a wide range of applications. Electrical and magnetic transport in such materials and their correlation with crystal structure have been investigated. All synthesized samples based on the sol-gel method are in the nanocrystalline range (27–38 nm) with the rhombohedral crystal system. The low electronic density was calculated from XRD patterns and the obtained results showed that a slight variation in electronic density is noted as a result of small cobalt substitution by iron in LaFe0.8Co0.2O3 and LaFe0.5Co0.5O3. A drastic increase in the electronic density was observed in LaFe0.2Co0.8O3 and again a decrease in the value of the electronic density in LaCoO3. IR spectra confirmed the formation of the proposed Perovskite crystal symmetry. Although the dc conductivity of all samples was small, we found a difference as a result of replacing iron with cobalt. The mechanism of electronic transfer in LaFexCo1-xO3 is mainly due to the electrons hopping between both Fe3+↔Fe2+ and Co3+↔Co2+ ions. Electrical measurements showed the semiconducting behavior of all samples. The optical properties studied by UV–Vis diffuse reflectance showed a large change in the optical energy gap with increasing Fe ions. All samples have a low energy band gap. The minimum Hci was 67G and the maximum was 715G as a result of doping. Magnetic hysteresis at room temperature showed antiferromagnetic order with weak ferromagnetism (canted antiferromagnetic order) enhanced with Fe content. The multi-domain grains appeared in La FexCo1-xO3 because the squareness ratio (Mr/Ms) in our case is in the range between 0.0 and 0.25.