Combining Near-Field Scanning Microwave Microscopy With Transport Measurement for Imaging Current-Obstructing Defects in HTS Films

Identification of defects that obstruct electrical current in high-temperature superconductors (HTS) is of great importance for applications. A technique that combines near-field scanning microwave microscopy (NSMM) with transport measurement was developed to obtain multiple sets of complementary maps on the same sample area. This technique takes advantage of the NSMM's unique capability to function both as an EM wave emitter that can locally heat a spot on a current-biased sample and also as a detector to map the spatial non-uniformity in electromagnetic properties of the sample including loss, dielectric constant, and surface morphology. Macroscopic defects in YBa
₂
Cu
₃
O
_7-delta
(YBCO) films were clearly identified and imaged using this technique with adequate sensitivity and resolution.