Electrical and pyroelectric properties of in-plane polarized lead lanthanum titanate thin film

Pb0.9La0.1Ti0.975O3 (PLT10) thin films were deposited on SiO2/Si(100) substrates coated with a ZrO2 buffer layer. Studies by x-ray diffraction and scanning electron microscopy reveal that the ZrO2 film consists of both tetragonal and monoclinic phases, with the tetragonal phase being the dominant one. The PLT10 film has a perovskite structure and the grains in the film have a rather uniform size of about 50 nm. By using interdigital transducer (IDT) electrodes the in-plane electrical properties, hysteresis loop, and pyroelectric coefficient of the PLT10 film were measured. The dielectric constant and loss factor vary only slightly with frequency in the range 10(3)-10(6) Hz, with the loss factor being less than 0.01 over the entire range. The leakage current density is lower than 2x10(-8) A/cm(2) at a bias field of 5 kV/cm. The remnant polarization and coercive field are 12.6 muC/cm(2) and 9.93 kV/cm, respectively. The film exhibits a reasonably high pyroelectric coefficient (95 muC/m(2) K) after it has been poled by applying 120 V ac at 0.1 Hz across the IDT electrodes. (C) 2001 American Institute of Physics.