STUDIES OF FERROELECTRIC FIELD EFFECTS IN PT PB(ZR0.5TI0.5)O-3/YBA2CU3O7 HETEROSTRUCTURES/

Pt/Pb(Zr0.5Ti0.5)O-3/YBa2Cu3O7 (Pt/PZT/YBCO) heterostructures were mad e by pulsed laser deposition on (100)SrTiO3 or (100)LaSrGaO4 substrate s for studies of ferroelectric field effects in high-T-c superconducti ng thin films. X-rag diffraction data, including Phi scans, indicated that the PZT layer grew with c-axis orientation epitaxially on top of the YBCO layers. Polarization measurements at room temperature and 77 K showed similar hysteretic loops in the PZT layer, The remanent polar ization field can induce as many as 10(14) carriers/cm(2) in the botto m superconducting channel at the interface. Both c-axis and in-plane-a ligned n-axis-oriented YBCO films, typically exhibiting zero resistanc e transition temperature of similar to 85 K, were used as superconduct ing channels. By polarizing the PZT film, a 2-5% change in both the ch annel resistance and the critical current at 77-85 K was obtained in s imilar to 100 nm thick films. Device operation at microsecond speeds w as observed.