Dielectric Relaxation of Al-Doped BaTiO3

概要

論文の詳細を見る
The Curie point ($T_{\text{c}}$) of Ba(Ti1-xAlx)O3-δ shifted to lower temperatures as the Al content ($x$) was increased. In the high-temperature region (${>}350$ °C), dielectric constants markedly increased with increasing temperature. At lower frequencies (${<}1$ kHz), dielectric constants steeply decreased with increasing frequency. At ${>}1$ kHz, dielectric constants were independent of frequency regardless of Al doping level. Dielectric loss ($\tan\delta$) peaks moved to higher frequencies with increasing Al content ($x$) in the Ba(Ti1-xAlx)O3-δ system ($0.0005 \leq x \leq 0.02$) at 250 °C. The activation energy was estimated to be 0.42–0.65 eV at 150–300 °C and 0.90–1.06 eV at 350–500 °C. The activation energy at higher temperatures could be due to the extra energy required for the dissociation of the defect complex (AlTi$'$–VO••) in addition to the dipolar motion of oxygen vacancies. Second phases were detected in the specimen doped with 2.0 mol % Al. As the Al content was increased, the lattice parameters (a and c) of Ba(Ti1-xAlx)O3-δ decreased within the solubility limit ($x\leq 1.0$ mol %).
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2009-03-25