Flux Growth of Pure and Lanthanum (La3+)-Substituted Bi4Ti3O12 Single Crystals and Their Characterization

概要

論文の詳細を見る
In this paper, we report the growth of pure Bi4Ti3O12 (BIT) and Bi4-xLaxTi3O12 ($x=0.25$, 0.50 and 0.75) single crystals by high-temperature solution growth (flux growth). The effects of La substitution on structural, optical transmission, ionic conductivity, dielectric constant and ferroelectric properties have been studied. Powder X-ray diffraction (XRD) and Differential thermal analysis (DTA) results reveal that the presence of La increases lattice constant (along the $b$- and $c$-axes) and liquidus and crystallization temperature of BIT. The deviation in La concentration in grown crystals from the initial La concentration was revealed by Energy dispersive X-ray analysis (EDAX). The incorporation of La ions also shifts the fundamental absorption edge in the UV–vis spectrum towards the higher-energy region and changes the absorption coefficient of BIT. Decreases in the dielectric constant, loss factor and ionic conductivity of BIT were observed with an increase in La concentration. Although, a significant improvement in remnant polarization was observed in $P$–$E$ studies, La incorporation markedly increased the coercive field of BIT.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2006-02-15