STRUCTURE AND POLARIZATION IN EPITAXIAL FERROELECTRIC PBZR0.52TI0.48O3 YBA2CU3O7-X/ND-YALO3 THIN-FILMS/

We fabricate epitaxial PbZr0.52Ti0.48O3/YBa2Cu3O7-x submicron film fer roelectric/superconductor heterostructures on the single-crystal YAlO3 +1%Nd2O3 substrate by the pulsed laser deposition technique. Frequency independent low loss tan delta=0.04 and dielectric constant of 950, h igh electric resistivity rho (150 kV/cm)=6x10(11)Omega cm, remnant pol arization of 32 mu C/cm(2), no visible fatigue after 10(7) short bipol ar pulses switching indicate excellent electrical performance of the n ew capacitor structure. The slight crystallite polar axis misalignment and depolarizing effect were found to be responsible for the shape of the apparent polarization loop. The only fitting parameter depolarizi ng coefficient N=2.37x10(-4) gives the best fit between theory and exp erimental data and corresponds to prolate ellipsoidal shaped crystalli tes with the length-to-diameter ratio of 140. (C) 1998 American Instit ute of Physics.