Modeling of Vortex Paths in HTS

A random walk model of the vortex paths in high temperature superconductors is investigated for different relative densities of c-axis, ab-plane and point pinning defects. The model suggests an origin for some of the more unusual features seen in the field angle dependence of the critical current. It also predicts greater noise in critical currents for fields parallel to the plane of the dominant pinning defects and anomalous behavior of n-values. The random walk model also suggests an alternative form for the expected field angle dependence of the upper critical fields in disordered layered superconductors.