Pyroelectric properties of (Pb1-xLax)TiO3 thin films deposited using SrRuO3 as a buffer layer

In this study, we observed that the ferroelectric properties of (Pb1-xLax)TiO3, (PLT) thin films deposited on Pt/Ti/Si substrates using SrRuO3 as a buffer layer change markedly with the substrate temperature and the composition. All the films are perovskite with no secondary; phases when deposited at 500-600 degrees C. However, only the films deposited below 520 degrees C possess a satisfactory small leakage current density, for example, J(L) less than or equal to 10(-7) A/cm(2); under a 50 kV/cm applied field. Both PLT10 (x = 0.10) and PLT5 (x = 0.05) thin films thus obtained possess large pyroelectric coefficient (p = 0.009-0.018 degrees C-1). However, the PLT10 thin films show pyroelectric properties markedly superior to the PLT5 thin films, although the PLT5 thin films own much better ferroelectric properties. This phenomenon is explained by the;lower Curie temperature (T-c) of the PLT10 materials. (C) 1998 American Institute of Physics. [S0003-6951(98)02225-6].