Most of the present applications of superconducting materials utilize metallic low-T{sub}c (LTS) materials. Their good mechanical properties, the advanced technology, and the excellent electrical performance at low temperatures provide a solid basis for a well-established market. High temperature superconductors (HTS) have, however, enough potential to be strong competitors to LTS. Their main advantage is certainly the T{sub}c above liquid nitrogen temperature and very high irreversibility field. Besides their excellent properties in many directions, a big reserve is still in technology optimization, in a theoretical understanding of the HTS superconductivity and flux dynamics in these materials. This plays in favor of HTS and will certainly lead to a continuous improvement of their position on the market. A special interest is here devoted to pinning in bulk (RE)Ba{sub}2Cu{sub}3O{sub}(7-δ)(RE-123) superconductors. Most applications of these materials utilize the peak effect (PE). While the character of relevant pinning is well known being identified with a point-like pinning disorder, the actual sources of this kind of pinning and the mechanisms of interaction with magnetic flux are still a matter of controversial discussions.
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