Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

摘要

We have used the LTLSM technique for a spatially resolved investigation ofthe microwave transport properties, nonlinearities and material inhomogeneitiesin an operating coplanar waveguide YBa_2Cu_3O_{7-\delta} (YBCO) microwaveresonator on an LaAlO_3 (LAO) substrate. The influence of twin-domain blocks,in-plane rotated grains, and micro-cracks in the YBCO film on the nonuniform rfcurrent distribution were measured with a micrometer-scale spatial resolution.The impact of the peaked edge currents and rf field penetration into weak linkson the linear device performance were studied as well. The LTLSM capabilitiesand its future potential for non-destructive characterization of the microwaveproperties of superconducting circuits are discussed.