Influence of Adjacent Nonsuperconducting Layers on Critical Parameters of an Inhomogeneous Superconducting Layer

The paper describes a method for calculating critical parameters of an inhomogeneous superconducting layer surrounded by nonsuperconducting layers. The calculation is performed using Ginzburg‒Landau equations modified for a thickness-inhomogeneous superconducting layer. The effect of adjacent nonsuperconducting layers is specified using general boundary conditions to these equations. Dependences of the critical current of a superconducting layer on the external magnetic field is calculated numerically. It is shown that for a layer of inhomogeneous thickness, in the model of which the effect of adjacent layers is introduced, an estimate of the critical current yields lower values than those for a homogeneous layer without any influence of boundaries. It is found that at a certain value of the external magnetic field, the critical current is independent of the degree of the superconducting layer inhomogeneity. In this case, the influence of adjacent layers on its superconducting state does not lead to a significant change in the value of this field.