Structure and polarization in epitaxial ferroelectric PbZr0.52Ti0.48O3/YBa2Cu3O7-x/Nd:YAlO3 thin films

Department of Electrical and Computer Engineering, Kumamoto University, Kumamoto 860, Japan
Applied Physics Letters (Impact Factor: 3.3). 03/1998; 72(5):620 - 622. DOI: 10.1063/1.120824
Source: IEEE Xplore


We fabricate epitaxial PbZr 0.52 Ti 0.48 O 3 /YBa 2 Cu 3 O 7-x submicron film ferroelectric/superconductor heterostructures on the single-crystal YAlO 3 +1%Nd 2 O 3 substrate by the pulsed laser deposition technique. Frequency independent low loss tan  δ=0.04 and dielectric constant of 950, high electric resistivity ρ (150 kV/cm)=6×10 11 Ω cm , remnant polarization of 32 μ C/cm 2 , no visible fatigue after 107 short bipolar pulses switching indicate excellent electrical performance of the new 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 depolarizing coefficient N=2.37×10-4 gives the best fit between theory and experimental data and corresponds to prolate ellipsoidal shaped crystallites with the length-to-diameter ratio of 140. © 1998 American Institute of Physics.

Download full-text


Available from: Alex Grishin
  • [Show abstract] [Hide abstract]
    ABSTRACT: The (001) preferred orientation of Nb-doped Pb(Zr0.52Ti0.48) O3 (PZT) thin films was successfully realized on amorphous glass substrate with LaNiO3(LNO) as electrode by rf-sputtering method. It was found that the LNO film greatly promotes formation of the PZT film with pervoskite phase on amorphous substrate and the preferred orientation of the PZT film depends strongly on the process of preparation. The experimental results show that the dielectric constant and loss of the PZT films with the (001) preferred orientation are 1308 and 0.042, respectively, at 1 kHz, 0.05 V. The remanent polarization (Pr), saturation polarization (Ps) and coercive field (Ec) are 34.5, 43 C/cm2 and 105 kV/cm, respectively. The PZT films also show a 33 kV/cm internal bias field due to its (001) preferred orientation. The piezoelectric coefficient d33 of the PZT film without the poled treatment is about 15 pC/N due to its (001) preferred orientation. The effect of the foreign stress on the piezoelectric voltage response of the PZT/LNO/glass was investigated. The results make us consider using the PZT film as an artificial skin to realize the self-diagnosis of amorphous materials under the action of stress.
    No preview · Article · Jan 1999 · Journal of Materials Science
  • [Show abstract] [Hide abstract]
    ABSTRACT: The three-terminal devices Ag/Pb(ZrxTi1−x)O3/YBa2Cu3O7−δ(Ag/PZT/YBCO) have been fabricated onto (100) SrTiO3 by pulsed laser deposition technique and photolithography. For the purpose of application, we specially selected the PZT layer with morphotropic phase boundary composition as the gate to lower the coercive fields and decrease the operating voltage. We tried to minimize the electrode area to 6×10−6 cm2 for deeply investigating the leakage problem and getting sufficient polarization of the PZT gate, also for the high integration in future application. From the process, we obtained the following results at 64 K: the saturation polarization and the remanent polarization reach 60 and 41 μC/cm2, respectively. The coercive field is lower than 37 kV/cm, and the breakdown field is ≥ 3×105 V/cm. The electric field effect measurement shows that the maximum modulation channel resistance ΔRDS/RDS is 3% under the gate voltage of ±9 V at 64 K (lower than the zero resistance temperature TC0, 70 K), at which the superconducting and normal state transition is driven by channel current IDS(IDS>Ic, Ic = 15 mA). © 1999 American Institute of Physics.
    No preview · Article · Apr 1999 · Applied Physics Letters
  • [Show abstract] [Hide abstract]
    ABSTRACT: The dielectric permittivity, loss tan δ, and polarization P-E loop in epitaxial pulsed laser deposited Nb:Pb(Zr0.52Ti0.48)O3 (600 nm)/YBa2Cu3O7−x(200 nm)/LaAlO3 heterostructures have been measured at high pressures of Gpa range. Remnant polarization has been found to decrease monotonously while the dielectric permittivity increases 1.5 times with the hydrostatic pressure increase up to 1 GPa. Superlinear pressure dependence of polarization has been found and explained in terms of mismatch stress which prevails in the low pressure range and is prominent in nanostructured ferroelectric layers. This effect also corresponds to recently observed correlation between the ferroelectric and nanocrystalline structure of highly c-axis oriented thin ferroelectric films.
    No preview · Article · Jul 1999 · Nanostructured Materials
Show more