Tailoring optical, magnetic and electric behavior of lanthanum strontium manganite La1−xSrxMnO3 (LSM) nanopowders prepared via a co-precipitation method with different Sr2+ ion contents

Abstract

Lanthanum strontium manganite (LSM) nanopowders La_1−xSr_xMnO₃ (x = 0.2, 0.5, 0.8) have been synthesized using the co-precipitation method based on methyl amine as a base at a pH value 12. The effect of Sr²⁺ ion concentration on the crystal structure, microstructure, optical, magnetic and the electrical properties was investigated. Typically, in all of the formed LSM powders, XRD revealed that a pure single perovskite LSM phase was obtained after annealing at 1000 °C for 2 h. This temperature was relatively low compared to what has been reported elsewhere. The microstructure of the produced LSM nanopowders depends on the Sr²⁺ concentration. The observations of these powders confirmed their rough surface. Meanwhile, the transmittance of the sample was around 40% for LSM with an Sr²⁺ ratio of 0.8. Furthermore, the band gap energy of this powder was 2.6 eV. The refractive index was decreased with an enhanced Sr²⁺ ion content. Indeed, the saturation magnetization of the LSM powders was increased on increasing the Sr²⁺ ion concentration. Electrochemical impedance spectroscopy (EIS) evinced that the electrode specific polarization resistance of the LSM samples was increased by increasing the Sr²⁺ ion concentration from 3.10 to 8.56 Ω cm².