Abstract
La0.9Sr0.1MnO3 nanoparticles were prepared using the citrate-gel route and sintered at different temperatures (T-s = 600 degrees C, 800 degrees C, and 1000 degrees C). The x-day diffraction patterns reveal that the samples exhibit a single phase with a rhombohedral (R (3) over barC) structure. The transmission electron microscopy technique shows an increase in the grain size when the sintering temperature (T-s) rises. The obtained values are approximately similar to that of crystallite size calculated from x-ray diffraction patterns. The impact of sintering temperature (T-s) on the electrical properties of La(0.9)Sr(0.1)MnO(3)manganite is examined using the impedance spectroscopy technique. A metal-semiconductor transition at a specific temperature (TM-SC) is observed for all samples. Indeed, the sintering temperature increase induces the shift of this transition temperature toward higher temperatures. Such a behavior is explained by the increase in the grain size. An agreement between the metal-semiconductor transition values coming from the DC resistivity and the grain boundaries analyses is observed. This agreement proves the contribution of the grain boundaries in the electrical properties of the studied samples. In addition, the presence of the relaxation phenomenon is confirmed. The fitted Nyquist plots show the correlation between the microstructure of the material and the electrical properties using an electrical equivalent circuit model. The DC resistivity and the impedance analyses reveal the thermal activation of the transport properties in the investigated system.