Study on structural, magnetic and electrical properties of perovskite lanthanum strontium manganite nanoparticles

Lanthanum Strontium Manganite (La_1−xSr_xMnO₃) perovskite nanoparticles are prepared by ultrasonication assisted hydrothermal method with different Sr concentration (x = 0.1, 0.3, 0.5). The structural, magnetic and electrical properties of the prepared samples are studied by powder X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometry (VSM) and impedance spectroscopy. The Powder XRD and EDX studies confirmed the formation of LaSrMnO₃. The powder XRD patterns show that the crystallite size decreases from 27.2 to 19.7 nm as the Sr concentration increases from x = 0.1 to x = 0.5. A shift in peak position towards higher angle indicates the replacement of La ions by Sr ions in the LaMnO₃ lattice. Electron microscopic images show that the La_1−xSr_xMnO₃ samples having both spherical and polygon morphology with decreasing particle size as the Sr concentration increases. The selected area electron diffraction (SAED) pattern confirms the polycrystalline nature of the La_1−xSr_xMnO₃(x = 0.5) nanoparticles. The magnetic study indicates that the La_1−xSr_xMnO₃ samples exhibits ferromagnetism at room temperature, which increases with increasing of Sr concentration. Dielectric analysis shows the dielectric constant decreases with the function of frequency and increases with Sr content. With increase in frequency and Sr ions dopant concentration, the AC conductivity of the prepared samples is increased. The Cole–Cole plot shows the different radii of the semicircles exhibit the resistances of La_1−xSr_xMnO₃ samples are highly dependent on the Sr concentration.