Study of the solubility of La3+-Dy3+ defect complexes and dielectric properties of (Ba1-xLax)(Ti1-xDyx)O-3 ceramics

摘要

Based on the double-site compensation mode, the solubility of La-Ba(center dot)-Dy-Ti' defect complexes and the dielectric properties of (Ba1 - x Lax) (Ti1 - Dy-x(x))O-3 (0.03 <= x <= 0.20) ceramics (BLTD) were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, electron paramagnetic resonance (EPR), and dielectric measurements. The solid solubility of La-Ba(center dot)-Dy-Ti' defect complexes in the BaTiO3 lattice was determined to be x=0.17. With an increase in x, the increase in the unit cell volume was linear and satisfied Vegard's law. The dielectric-peak temperature (T-m) decreased rapidly at a rate of -23 degrees C/at% La-Ba(center dot)-Dy-Ti' The BLTD ceramics with x=0.05 and 0.07 met the Y5V specification with a higher room-temperature permittivity (epsilon(RT)' similar to 4000 and 3000) and a lower dielectric loss (tan delta < 0.04). A weak g=2.004 EPR signal associated with ionized Ti-vacancy defects appeared in all of the BLTD ceramics. The exclusive occupations of La3+ ions at Ba sites and the preference for the self-compensation mode by Dy3+ ions are responsible for the formation of predominant La-Ba(center dot)-Dy-Ti' defect complexes and the appearance of the minute concentration of Ti vacancies and Dy-Ba(center dot)-Dy-Ti' defect complexes. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.