Dielectric and Ferroelectric Characterization of Ba.

Barium titanate (BaTiO) has been doped in situ with 5 mol% thulium by a sol-gel method. The as-prepared gel powder consists of nanosized grains (20-30 nm) and crystallizes on the cubic BaTiO lattice, at 700°C. BaTmTiO ceramics derived from this powder have tetragonal perovskite structure and contain a small amount of TmTiO pyrochlore phase. These ceramics exhibit dielectric constants of 4282-3240 and dielectric loss (tan δ) of 0.1077-0.0161 at Curie temperature T=132°C and at 10 Hz-100 kHz, respectively. For a drive voltage of 400 V, the hysteresis loop recorded at the frequency of 100 Hz shows a remnant polarization ( P) value of 76 μC/cm and a coercive field ( E) of 124 V and for 1 kHz a remnant polarization ( P) value of 58 μC/cm and a coercive field ( E) of 116 V. [ABSTRACT FROM AUTHOR]