Magnetoresistance Anisotropy of a One-Dimensional Superconducting Niobium Strip

We investigated confinement effects on the resistive anisotropy of a superconducting niobium strip with a rectangular cross section. When its transverse dimensions are comparable to the superconducting coherence length, the angle dependent magnetoresistances at a fixed temperature can be scaled as R(θ,H)=R(H/H_cθ) where H_cθ=H_c0(cos⁡²θ+γ^-2sin⁡²θ)^-1/2 is the angular dependent critical field, γ is the width to thickness ratio, and H_c0 is the critical field in the thickness direction at θ=0°. The results can be understood in terms of the anisotropic diamagnetic energy for a given field in a one-dimensional superconductor.