Abstract
The elementary pinning force of a small normal precipitate is calculated by using the phenomenological Ginzburg–Landau equations. The resultant elementary pinning force is almost the same as or slightly larger than that of a void of the same size. This contradicts the theoretical result of Kramer and Freyhardt that the elementary pinning force of the normal precipitate smaller than the coherence length is significantly smaller than that of the void due to the proximity effect. It is pointed out that the normal precipitate was incorrectly regarded as an inherent weak superconductor in the theory of Kramer and Freyhardt. The present theoretical result is compared with the result of a previous experiment and satisfactory agreement is obtained.