Pyroelectric and dielectric properties of lead lanthanum zirconate titanate (Pb0.92La0.08)(Zr0.65Ti0.35)O3-P(VDF/TFE)(0.98/0.02) nanocomposites

PLZT-P(VDF/TFE) 0-3 composites with nanosized lead lanthanum zirconate titanate (Pb0.92La0.08)(Zr0.65Ti0.35)O-3 (PLZT 8/65/35) ceramic powders of volume fraction I broken vertical bar up to 0.2 were fabricated using PLZT powders imbedded in a copolymer P(VDF/TFE)(0.98/0.02) matrix. The PLZT nanopowders were prepared by the sol-gel technique. The PLZT-P(VDF/TFE) composite samples were prepared from ceramic and polymer powders by the hot-pressing method. Dielectric response was studied in the frequency range from 100 Hz to 1 MHz and at temperatures from 100 to 450 K. The pyroelectric properties were studied by dynamic method with modulation frequency from 1 to 100 Hz. The dielectric response of the ceramics-polymer composite was found to be a combination of the responses of the pure polymer and the ceramics: (1) the addition of the PLZT ceramics increases the value of the dielectric permittivity E >', (2) the composite shows the maximum of the permittivity coming from the PLZT ceramics, (3) the temperature dependences of the dielectric loss tg delta are characterized by the maximum attributed to the alpha-relaxation (glass transition) in the pure polymer. The pyroelectric coefficient of the composite increases from similar to 20 mu C/m(2)K in pure P(VDF/TFE) to similar to 140 mu C/m(2)K in the composites of I broken vertical bar aEuro parts per thousand= 0.15.