Effect of flux creep on irreversibility lines in superconductors

It is known that the irreversibility line depends on the flux pinning strength, the dimensionality of the superconductor originating from the crystal structure and the size of the superconductor. The important parameter which determines the irreversibility line is the pinning potential. The pinning potential is related to the above three factors through the depth of the pinning potential well per unit volume of the fluxoid lattice and the volume of the flux bundle. In order to investigate quantitatively the effect of these factors on the irreversibility line, a numerical analysis is carried out using the flux creep model. The critical current density and the irreversibility field are determined from the obtained current-voltage curves. These results are compared with experimental results on various high-T-c superconductors.