Abstract: In this work, the La0.8Sr0.2Fe1-xMgxO3 (x = 0.1, 0.2, and 0.3) perovskite materials were successfully prepared by the sol-gel method through the sintering process to form bulk material. The analysis of XRD indicated that these perovskite materials are well fitted with the Pbnm space group and an orthorhombic structure. The lattice parameters and crystallite size increase with the increase of Mg substitution, indicating that the presence of Mg2+ in the crystal lattice inhibits the growth of the crystallite size. By Impedance Spectroscopy using RLC meter, the electrical properties of the material as a function of frequency (100Hz-7MHz) at room temperature was measured. According to the Nyquist plot and the Bode plot, the conductivity of La0.8Sr0.2Fe1-xMgxO3 contributed by the grains and grain boundaries. Nyquist plot of complex impedance becomes higher with Mg substituted due to hole carrier. Real part impedance analysis explains the existence of space charge polarization at low frequency. The diameter of the semicircle increases from increasing to doping with magnesium. This means that doping with magnesium will cause the resistance of the material to increase. The impedance data shows that as the Mg content increases, the impedance value decreases. According to dielectric research, dielectric spectroscopy shows that as Mg doping increases, the dielectric loss increases and the dielectric constant (ε') of samples decreases at a lower frequency.
Keywords: impedance spectroscopy, Sol-gel method, La0.8Sr0.2Fe1-xMgxO3 (La,Sr)(Fe,Mg)O, x-ray diffraction; electrical properties