Abstract
Measurements of superconducting transition in terms of complex susceptibility have been well known as one of the useful methods for studying the superconducting properties of materials. By applying this method to oxide superconductors, we have found that sintered specimens consist of the bulk superconducting phase and the weak-link coupling phase. Typical experimental results observed for some kinds of oxide superconductors as well as those of thin film single crystals are presented.
