Critical temperature profile determination using a modified London equation for inhomogeneous superconductors

A modified form of London's equation describing the penetration of magnetic flux into an inhomogeneous superconductor is derived from the Ginzburg-Landau theory. This equation takes into account spatial variation of the magnetic penetration depth. The magnetic flux penetration into an inhomogeneous superconducting slab is calculated and a method is described whereby the spatial variation of the critical temperature can be obtained from an inductive T/sub c/ transition. The consequences of using other sample geometries and the relevance of this work to the characterization of practical superconducting wires is discussed