The interaction between a single vortex and a columnar defect in the superconducting multilayers

Abstract

The interaction energy per unit length U int( r) between a single vortex and a columnar defect with radius a in the superconducting multilayers is calculated with the help of London theory. We assume that these superconducting layers are coupled by the magnetic field and the interlayer Josephson coupling can be neglected. We obtain a general expression of U int( r) for any t, where t is half of the spacing between the layers. For t → ∞, our theory can be reduced to the result of a thin film. But when t becomes smaller, U int( r) would tend to exhibit the behavior of 3D superconducting bulk.