  A unified approach for description of the anomalous critical current
enhancement in dislocated, deoxygenated, and particle irradiated
superconductors is proposed based on a novel concept of "active pinning"
(pinning via external fields modified intrinsic Josephson junctions) and
existence of various competitive forces affecting a rather delicate balance
between extended defects (dislocations) and point defects (oxygen vacancies)
inside a crystal. The proposed scenario implies that practically any treatment
of the superconducting sample (such as sintering, melt-texturing, silver
coating, thermal and mechanical treatment, oxygenation/deoxygenation process,
particle irradiation, application of high magnetic and electric fields) will
inevitably result in a "self-organized" rearrangement of the pre-treated defect
structure of the material to optimize its pinning ability.
