Microwave surface resistance ofYBa2Cu3O7-δ films onpolycrystalline alumina and Ni-based alloy substrates withion-beam-assisted-deposited buffer layers

摘要

We measured the microwave surface resistance Rs of superconducting YBa2Cu3O7-x(YBCO) films on buffered polycrystalline alumina and Ni-based alloy substrates using parallel-plate technique. We observed a strong between the low-power R s and the in-plane mosaic spread of the YBCO films. A 0.4-μm-thick YBCO film with an in-plane mosaic spread of 6.60 (7°) on a buffered polycrystalline alloy (buffered polycrystalline alumina) showed an Rs of 0.51 mΩ (1.89 mΩ) at 76 K and 0.17 mΩ (0.21 mΩ) at 4 K