Polarization correlation and pyroelectric properties of Pb(Zr, Ti)O₃ and La doped Pb(Zr, Ti)O₃ multilayer thin films

Polarization correlation was found in the alternatively deposited Pb(Zr, Ti)O₃ (PZT 30/70) and La doped Pb(Zr, Ti)O₃ (PLZT 17/30/70) multilayered thin films prepared by a modified sol-gel process. HRTEM results revealed that the multilayered thin films had their (111)-preferred orientation and crystalline size of 300 nm. Dielectric constants and losses at 1 kHz for the un-poled sample and the sample poled at 357 kV/cm were 880, 800, and 0.022, 0.019 respectively. A high pyroelectric current was observed in the PZT/PLZT multilayered thin film near the PLZT phase transition point even after several thermal cycles above the phase transition temperature of the PLZT layer. This phenomenon was termed as the self-biased dielectric bolometer (SBDB) effect, and was attributed to the induced polarization in PLZT layers by the remnant polarization in their adjacent PZT layers.