Defect Control for Large Remanent Polarization in Bismuth Titanate Ferroelectrics –Doping Effect of Higher-Valent Cations–

Abstract

The effects of concentration and distribution of defects controlled by quenching and doping of higher-valent cations on the ferroelectric properties of dense Bi₄Ti₃O₁₂ ceramics were investigated. The remanent polarization (P _r) of non-doped ceramics quenched from 800°C (above the Curie temperature) was twice as large as those of samples subjected to slow cooling to 25°C and quenched from 600°C (below the Curie temperature). These results imply that domain pinning by defects dominates the polarization properties. The incorporation of vanadium and tungsten into Ti site significantly reduced the influence of domain pinning, resulting in a very large 2P _r of over 40 µC/cm².