Anomalous peak-effect in type-II superconductors: A competition between bulk pinning and a surface barrier

In this work, the joint influence of the surface barrier and bulk pinning on the magnetic-field dependence of the critical current Ic for bulk type-II superconductors is investigated. It is shown that in the weak magnetic field H0, there is a section in the dependence Ic(H0) in which Ic increases with the growth of H0; this increase results in a pronounced peak in the dependence Ic(H0) – the anomalous peak-effect. This effect is explained by the combined influence of the surface barrier and bulk pinning. Two well-known models – the Bean model and the Kim–Anderson model – of the critical state were analysed in order to describe the anomalous peak-effect quantitatively.