Low-field microwave absorption in bismuth-based high-Tc superconducting single crystals: threshold vortex-lattice effects
Bursian V. E. , Bush A. A. , Vikhnin V. S., Gladyshev I. V., Sochava L. S.
A threshold in the magnetic field has been observed for several characteristic effects in the low-field absorption by high~rc single crystals. A signal of a new type corresponds to the threshold field in the microwave absorption spectrum. The appearance of the new signal in the low-field absorption and of effects which involve a threshold in the magnetic field is linked with a transition from an individual pinning of vortices to a collective pinning.