Structural and Dielectric Properties of La3+/Mn4+ Modified Lead Titanate Nanoceramics

Abstract

The nanocrystalline samples of Pb0.94La0.06MnxTi1-xO3 (PLMT) (x =0, 0.04, 0.07, 0.10) were prepared by using a novel mechanical
activation followed by a conventional solid-state reaction technique. The calcination and sintering temperatures were optimized by thermal gravimetric analysis and repeated firing. Phase analysis using high resolution X-ray diffraction technique at room temperature suggests that compounds are formed in a single phase with tetragonal crystal system. The field effect scanning electron microscopy (FESEM) shows that materials have well-defined granular microstructures, separated by the grain boundaries. Measurement of dielectric properties (dielectric constant and dielectric loss) as a function of frequency and temperature were realized in PLMT ceramics. It shows a shift in the transition temperature towards the lower-temperature side with La3+/Mn4+ substitution. The
electrical conductivity calculated from impedance data has been observed to increase as a function of Mn concentration. The ac conductivity spectrum analysis suggests hopping of charge carriers among localized site as the possible mechanism for electrical conduction.