Mechanism of modulated microwave absorption and flux distribution in granular YBa2Cu3Ox under high field sweep

The mechanism of modulated microwave absorption (MMA) is suggested from the modulation (Hm) dependence in granular YBa2Cu3Ox superconductor under high-field sweep. It is proposed that the MMA signal S be decomposed into three shape factors to interpret the experimental result. The VN factor arises from the difference in the number of vortices between the add (A) mode and the subtract (S) mode corresponding to the alternating field. The CT factor arises from the appearance of the transition region of the shielding current in the S-mode where the absorption is less. The SS factor arises from the difference in the surface slope of the flux distribution between the two modes. With increasing Hm, the positive VN increases linearly. The positive CT increases initially and then decreases. The slope for the A-mode is very gentle, so that SS is negative, and it initially increases rapidly and then saturates. These factors can reproduce the complex behavior of the Hm dependence of S fairly well