Disorder-Driven Magnetic Field Dependence of the Internal Field Distribution in the Bragg Glass Phase of Type-II Superconductors

TL;DR

This paper investigates how weak point disorder affects the internal magnetic field distribution in the Bragg glass phase of type-II superconductors, revealing an extrinsic, disorder-driven magnetic field dependence observable in NMR and muon-spin rotation experiments.

Contribution

It introduces a replica variational method analysis showing disorder-induced magnetic field dependence unrelated to pairing symmetry in type-II superconductors.

Findings

Magnetic field variance depends significantly on external field strength.

The dependence is extrinsic and driven by disorder, not microscopic pairing mechanisms.

Results are applicable to interpreting NMR and muon-spin rotation data.

Abstract

We use the replica variational method to study the effects of weak point disorder on the variance of the internal field distribution measured in NMR and muon-spin rotation experiments in type-II superconductors. We show that for a simple model there is significant magnetic field dependence which is extrinsic and disorder-driven, and does not have a microscopic (non $s-$wave pairing) origin. Results are presented where we examine the dependence of the magnetic field variance upon the strength of the applied external field.