Interatomic chemical bonding and charge correlation of optical, magnetic and dielectric properties of La_1−xSr_xFeO₃ multiferroics synthesized by solid- state reaction method

Strontium (Sr) substituted LaFeO₃ (La_1−xSr_xFeO₃) (x = 0.05, 0.10, 0.15 and 0.20) multiferroics were synthesized by the conventional high temperature solid-state reaction method. The X-ray diffraction was used to analyze the phase formation and purity of La_1−xSr_xFeO₃ multiferroics. The X-ray diffraction patterns confirm that all the samples are monophasic with orthorhombic structure. The charge density distribution and the interatomic chemical bonding between the neighbouring atoms in the unit cell were examined using the structure factors obtained through the refinement process. SEM micrographs were used to observe the surface morphology and to determine the average particle size. UV–Vis spectrographs and magnetic hysteresis (M–H) loops from magnetic measurements were exploited to investigate the optical and magnetic behavior of the samples. The magnetic hysteresis loops indicate that the prepared La_1−xSr_xFeO₃ multiferroics exhibit ferromagnetic behavior. Ferromagnetism was observed to be relatively prominent for x = 0.05 sample, with high values of magnetic parameters such as M_s, M_r, and H_C as 2.4 emu/g, 1.12 emu/g, and 1616 G respectively. The dielectric measurements indicate that the sample with Sr content x = 0.05, attains the giant value of dielectric constant of about 2.3 × 10⁵ and ac conductivity of about 0.2 Ω⁻¹m⁻¹ when compared to the other samples. The optical, magnetic and dielectric properties of La_1−xSr_xFeO₃ multiferroics have been examined and also have been correlated with the charge, bonding nature and the spin of the constituent ions which has not been explored in open literature so far.