Defect control for large remanent polarization in bismuth titanate ferroelectrics doping effect of higher-valent cations

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 degreesC (above the Curie temperature) was twice as large as those of samples subjected to slow cooling to 25 degreesC and quenched from 600 degreesC (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) over 40 muC/cm(2).