PREPARATION OF FERROELECTRIC (PB, LA)(ZR, TI)O3 THIN-FILMS BY SOL-GEL PROCESS AND DIELECTRIC-PROPERTIES

Crack-free transparent ferroelectric polycrystalline PLZT (Pb, La)(Zr, Ti)O3 thin films with perovskite structure were prepared by dipcoating from a sol-gel process. Lead acetate, lanthanum-acetate, zirconyl nitrate and titanium tetrabutoxide were used as the raw materials. Acetic acid and triethylene glycol were used as solvents. Ferroelectric polycrystalline PLZT thin films with perovskite structure were obtained between 400-degrees-C and 850-degrees-C in air. The thin films deposited on platinum substrates and on silica glass substrates with sputtered ITO thin film were smooth and uniform. The dielectric constant of PLZT (7/65/35) thin film on the platinum substrate was about 788 at room temperature for 10 kHz and the loss tangent was about 0.03. The spontaneous polarization of PLZT (7/65/35) thin film was 8.0-mu-C.cm-2 and the coercive field was 20 kV/cm. The optical transmittance was above 60% in the range from 400 nm to 900 nm.