Critical Current Limitations and Irradiation Effects in High-Temperature

The discovery of high-temperature superconductors stimulated many groups of researchers to study properties of these materials. From the basic point of view the most important problem is to clarify the mechanism of high-temperature superconductivity. From the practical point of view the most challenging task is to find mechanisms of strong pinning of the vortices, and thereby to obtain materials with high critical current density. The aim of this paper is to discuss problems connected with critical current limitations and to present possibilities which offer irradiation effects with respect to critical current enhancement