FLUX TRAPPING IN HIGH-TEMPERATURE SUPERCONDUCTORS DETERMINED BY MICROWAVE-ABSORPTION

Low-field microwave absorption has been applied for monitoring magnetic flux trapping in a ceramic sample of YBa2Cu3O6.9 in the presence of a microwave field. Magnetic field trapping is strongly dependent on the texture of a superconducting sample. On cooling of the sample in a magnetic field, the magnetic flux is observed to reach a saturated value. The observed phenomena are discussed in terms of the model of intergrain Josephson junctions where dissipation of energy takes place and is a source of microwave absorption. The proposed method is an important complement to classical methods of magnetization investigation, as it permits studies of the local distribution of magnetic flux trapped in a superconducting sample.