Ferroelectric bismuth titanate/superconductor (Y-Ba-Cu-O) thin-film heterostructures on silicon
Ramesh, Ramamoorthy, A. Inam, B. Wilkens, W.K. Chan, T. Sands, J.M. Tarascon, D.K. Fork, T.H. Geballe, J. Evans, J. Bullington
The growth by pulsed-laser deposition of c-axis-oriented bismuth titanate (BTO)/YBa2Cu3O7(YBCO) superconductor heterostructures on -oriented Si with epitaxial yttria-stabilized ZrO 2 as a buffer layer is reported. X-ray-diffraction studies of the heterostructures show that all the layers grow in the c-axis orientation, with a rocking angle of 1.0°-1.2°for the bismuth titanate layer and 0.6°-0.8°for the YBCO layer. Rutherford backscattering ion channeling yields of 28% at the surface have been obtained. Transmission electron microscopy of cross-sectioned samples reveal that the BTO layer has a significant density of translational boundaries that propagate at 45°to the film surface. The BTO film exhibits ferroelectric hysteresis and a dielectric constant in the range of 180-200.
Applied Physics Letters
Year of Publication