Pyroelectric Property of Pb_5Ge_3O_<11> Thin Films Prepared by Laser Ablation

概要

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Pb_5Ge_3O_<11> films were prepared by laser ablation, and pyroelectricity was obtained in the films after annealing. Stoichiometric films were formed at oxygen pressures around 5×10^<-1> Torr during deposition. It was found that an unreported precursor phase was grown on Pt/Ti/SiO_3/Si substrates at a temperature of 520℃. Subsequent annealing at 500℃ for 2 h in air made it possible for the film to have (001) oriented texture of ferroelectric Pb_5Ge_3O_<11>. This sample showed remanent polarization of 1.4 μC/cm^2 with a ferroelectric hysteresis loop of an asymmetric shape and a pyroelectric coefficient of 4.3 nC/cm^2K, while these values were about one third of those reported for single crystal Pb_5Ge_3O_<11> in a polarization direction. The inferiority in this ferroelectricity is thought due to the lead-deficient phase involved in the film. Although this localized second phase still remains, the appreciable reduction in the process temperature for texturing a Pb_5Ge_3O_<11> film in the c-plane as low as around 500℃ is attributed to the sufficient supply of oxygen during the deposition.
社団法人応用物理学会の論文
1995-09-30