Four-fold basal plane anisotropy of the nonlocal magnetization of YNi2B2C

TL;DR

This paper investigates the four-fold anisotropy of magnetization in YNi2B2C, revealing non-local electrodynamics effects in its superconducting state, which cannot be explained by traditional London theory.

Contribution

It demonstrates that generalized London theory with non-local effects explains the observed anisotropy, advancing understanding of superconductivity in clean, intermediate-k materials.

Findings

Four-fold anisotropy observed deep in the superconducting mixed state

Standard London theory cannot account for the anisotropy

Generalized London theory with non-local effects provides a good description

Abstract

Studies of single crystal YNi2B2C have revealed a four-fold anisotropy of the equilibrium magnetization in the square crystallographic basal plane. This pi/2 periodicity occurs deep in the superconductive mixed state. In this crystal symmetry, an ordinary superconductive mass anisotropy (as in usual London theory) allows only a constant, isotropic response. In contrast, the experimental results are well described by generalized London theory incorporating non-local electrodynamics, as needed for this clean, intermediate-k superconductor.