INTEGRATION OF LASER MBE GROWN OXIDE THIN FILMS OF SrTiO3 WITH YBa2Cu3Oy FOR TUNABLE APPLICATIONS

The frequency tuning can be achieved by integrating SrTiO3 (STO) thin films into high-temperature superconducting YBa2Cu3Oy (YBCO) devices and tuning the dielectric constant of the STO films by an electrical bias. We have fabricated epitaxial STO thin films on superconducting YBCO. By the combination of various surface characterizations such as scanning probe microscope, structural and dielectric measurements, we attempted to understand the fundamental mechanisms of dielectric properties in STO thin films. Substrate surface and structural properties of the heterostructure were studied. We have measured the temperature dependence of dielectric constant and loss tangent of STO thin films. The system exhibits 41% dielectric constant tuning over a bias of 4 V at low temperature.