Increasing the critical temperature of a superconductor by curving its surface

Laboratorium voor Vaste-Stoffysica en Magnetisme Katholieke Universiteit Leuven B-3001 Leuven, Belgium

Received: 30 June 2000
Accepted: 25 July 2000

Abstract

Using Ginzburg-Landau theory it is predicted that the critical temperature of a mesoscopic superconductor with surface enhancement can be increased significantly with respect to the bulk , by introducing surface curvature. While confinement and reduction of the dimensionality lead to a critical-point shift which decays exponentially with the ratio of sample size to coherence length, surface curvature gives rise to a more important algebraic shift proportional to the curvature . As an example, order-of-magnitude estimates for the increase of are given for cold-worked mesoscopic InBi cylindrical wires and spherical grains.