Eddy current technique for testing large-area, high T_c superconducting films with high spatial resolution

An eddy current technique has been developed which allows non-destructive quality testing of high temperature superconducting thin films with a spatial resolution of ≈50 μm. This technique allows inexpensive and fast diagnosis of large-area superconducting films on substrates with a diameter up to 6 in. The eddy current probe is scanned over the surface of the superconducting film without the need for extra electrical or mechanical attachments. Reports are given on experiments with both well defined test geometries and large-area epitaxial YBa₂Cu₃O_{7 - δ} films prepared on 4 in silicon wafers.