Switching kinetics of pulsed laser deposited epitaxial PZT films

We have fabricated epitaxial PbZr_0.52Ti_0.48O₃ (PZT, 40 approximately 1200 nm)/YBa₂Cu₃O_7-x (YBCO, 400 nm) film ferroelectric/superconductor heterostructures on the single-crystal neodymium doped yttrium monoaluminate [YAlO₃+1%Nd₂O₃] and MgO substrates by KrF pulsed laser deposition technique. The dielectric constant of 950 and loss tangent δ of 0.04 have been found to be frequency independent in the range 100 Hz to 100 kHz while electric resistivity ρ (150 kV/cm) is of 6×10¹¹ Ω·cm, remnant polarization and coercive field are 32 μC/cm² and 43 kV/cm, respectively. Fast ferroelectric switching kinetics with characteristic switching time around 50 ns has been observed. Universal electric field and temperature dependencies of switching time as well as film thickness dependence of coercive electric field have been observed and correspond to ferroelectric needle-like domain switching.