Magnetic-field-induced microwave losses in epitaxial Bi-Sr-Ca-Cu-O films

Magnetic-field-induced microwave losses in epitaxial c-axis-oriented Bi-Sr-Ca-Cu-O films have been observed. At low magnetic field, the behavior of the absorption is qualitatively analogous to that already observed in granular samples. The dominant part is attributed to the dephasing of a network of Josephson junctions. A structural analysis shows evidence of such a network. The dependence of the absorption on the angle between the magnetic field and the a-b plane is consistent with this model