Flux pinning mechanisms in type II superconductors

Expressions for flux-pinning in type II superconductors are derived from considerations of the nature of the interaction between individual flux-lines and pinning-centres, and of the geometry of the pinning-centres. It is demonstrated that the experimentally observed scaling laws are obtained without the necessity of introducing the concept of flux-lattice elasticity. Predicted pinning functions are found to provide adequate explanation of measured Lorentz force curves in a wide range of high- K , strong-pinning materials.