CONTROL OF FERROELECTRIC PROPERTIES OF PbZr_xTi_(1-x)O_3 THIN FILM FOR ELECTRON EMISSION DEVICE DRIVEN BY LOW VOLTAGE

摘要

Epitaxial PbZr_(0.52)Ti_(0.48)O_3/YBa_2Cu_3O_(7-x) heterostructures on Nd:YAlO_3 and MgO substrates were fabricated by KrF pulsed laser deposition. The coercive electric field of the PZT films increased with decrease of the film thickness from 1.2 μm to 0.04 μm, while the magnitude of spontaneous polarization was almost constant in this thickness range. It was found that the dependence of the film thickness d on the coercive electric field E_c was E_c∝ d~(-2/3). This results from that the PZT/YBCO heterostructure has the one dimensional ferroelectric domain growth without non-ferroelectric phase. The polarization of Au/PZT/YBCO/(MgO or YAlO) capacitors can be changed by the applied voltage below 5 V.