Sol-hydrothermal synthesis, crystal structures and excellent dielectric stability of yttrium doped BaTiO₃ceramics

Abstract

Monodisperse Yttrium-doped BaTiO3 (YBT) nanoparticles with good crystallinity and uniform size distribution have been synthesised via a modified sol-hydrothermal method. The solubility of yttrium in BT was no more than 1 mol%. However, at higher Y3+ content, excess Y3+ were inclined to form Y(OH)3 impurities, and after high temperature sintering, impurity YBa3Ti2O8.5 can be detected in the ceramics. Further, the variation in the crystal volume indicated that Y3+ preferred to substitute for Ti4+ as an acceptor. FE-SEM images revealed that the grain size of the ceramics gradually decreased with the raising Y3+ concentration. Notably, YBT ceramics with 3 mol% Y3+ presented outstanding dielectric-temperature stability, benefitting from the diffuse ferroelectric–paraelectric phase transition and the existence of YBa3Ti2O8.5 phases. Stable dielectric-temperature property and low dielectric loss of the YBT ceramics doping with 3 mol% Y3+ in the range from 1 kHz to 1 MHz render it as a promising candidate material for high frequency application.