Investigation Of The Structure, Surface Morphology And Dielectric Properties Of Pb_0.35Sr_0.65TiO₃ And Ba_0.1Sr_0.9TiO₃ Films By Pulsed Laser Deposition

PbxSr1-xTiO3(PST) and BaxSr1-xTiO3 (BST) have recently attracted considerable attention as promising candidates for applications in tunable microwave devices due to their high tunability of permitivity with DC bias. For tunable microwave device applications, the PST and BST thin films should own high tunability, low dielectric loss, low leakage current and smooth film surface,etc.In part one, Pb_0.35SR_0.65TiO₃ thin films have been fabricated on LaAlO3(LAO) and MgO substrates using the pulsed-laser deposition technique. We have compared the structure, surface morphology and dielectric properties of Pb_0.35SR_0.65TiO₃ thin films grown on LAO and MgO. The films grown on LAO show a better crystallinity and smoother surface, compared to the Pb_0.35SR_0.65TiO₃ thin films grown on MgO. The results indicate that the Pb_0.35SR_0.65TiO₃ thin films grown on LAO could have a better interface between top electrode and film. In addition, by contrast with the Pb_0.35SR_0.65TiO₃ thin films on LAO, the films grown on MgO show a larger grain size and dielectric constant. It indicates that the films grown on MgO have better dielectric properties, compared to the films on LAO. The experimental results show that a proper strain is properly applied to Pb_0.35SR_0.65TiO₃ thin films by substrate, which can improve the physical properties of Pb_0.35SR_0.65TiO₃ thin films. In part two, the fabrication, structure and dielectric properties ofPb_0.35SR_0.65TiO₃/YBa2Cu3O7-δ(YBCO) heterostructures grown on LAO and MgO have been studied. The results suggest that the structure and dielectric properties of...