LOWER JOSEPHSON CRITICAL-FIELD IN GRANULAR HTS MEASURED BY MICROWAVE-ABSORPTION

The method of magnetically modulated microwave absorption (MMMA) has b een used here to measure the lower Josephson critical field in a YBaCu O superconductor. The measurements based on the changes in the width o f the hysteresis of the MMMA signal which were observed while increasi ng the range of the magnetic field sweep were carried out. The effects observed by us are explained using the Clem model of the cubic array of superconducting grains. Also, a simple interpretation of the influe nce of the magnetic modulation on the measured value of the lower Jose phson critical field is provided.