PROBING SELF FIELD EFFECTS ON INTERGRAIN CURRENTS USING AN AC TECHNIQUE

Measurement of flux movements into a superconducting sample using an AC technique has been developed further to yield information about the dependence of the transport critical current density on field in a regime where interpretation of normal transport measurements is difficult due to self-field effects. The variation of J(c) with B can be extended to much lower fields than in bulk samples, which would have to be less than 0.1 mm thick to give a true zero-field critical current.