Microstructure study of YBa2Cu3O7-δ thin film with Synchrotron-based Three-dimensional Reciprocal Space Mapping

High-temperature superconducting films can be used for the fabrication of cutting-edge high-temperature superconducting microwave devices because of their low microwave surface resistance. However, the microwave surface resistance of high-temperature superconducting materials is particularly sensitive to microstructure due to their special two-dimensional superconducting mechanism and extremely short superconducting coherence length. To investigate the correlation between microstructure and microwave surface resistance of high-temperature superconducting materials, YBa2Cu3O7-δ (YBCO) films with different thicknesses were grown on (00l)-oriented MgO single-crystal substrates using pulsed laser deposition (PLD) technique. Electrical measurements revealed that their superconducting transition temperature and room temperature resistance do not show significant difference. However, their microwave surface resistance at superconducting state display a significant difference. The characterization of the microstructure of YBCO films by synchrotron radiation three-dimensional reciprocal space mapping(3D-RSM) technique shows that the number of the grains with CuO2 face parallel to the surface (c crystals), and the consistency of grain orientation are the main causes for the difference in microwave surface resistance.