Sintering Behavior, Dielectric and Pyroelectric Properties of <TEX>$(Pb, La)TiO_3$</TEX> Ceramics

,; ,; ,; ,

J. Korean Ceram. Soc. > Volume 31(8); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(8): 841.

$(Pb, La)TiO_3$ 세라믹스의 소결 거동 및 유전.초전 특성

최동구, 최시경

한국과학기술원 무기재료공학과

Sintering Behavior, Dielectric and Pyroelectric Properties of $(Pb, La)TiO_3$ Ceramics

ABSTRACT

The sintering behavior of La-modified PbTiO3 ceramics was investigated in order to improve the poor sinterability of PbTiO3. Addition of La improved the sinterability. It was confirmed that this improvement was due to the decrease in tetragonality ratio c/a of crystal lattice. The variations of dielectric constant and pyroelectric coefficient were measured with temperature. It was observed that with the increase of La content, Curie temperature decreased and dielectric constant at room temperature increased. La-modified PbTiO3 ceramics had smaller pyroelectric figure of merits than those of pyroelectric materials in use. The effects of grain size on dielectric and pyroelectric properties were also investigated. The change of grain size had effect on maximum dielectric constant and pyroelectric coefficient, but is had little effect on pyroelectric figure of merit at room temperature. The closer examination near ferro-paraelectric phase transition temperature revealed that the behavior of phase transition approached a more relaxor character with the increase of La content and the decrease of grain size.