Critical currents in weakly textured MgB2: Nonlinear transport in anisotropic heterogeneous media

TL;DR

This paper presents a model explaining how the anisotropic structure of MgB2 superconductors influences their critical current behavior, aligning theoretical predictions with experimental observations.

Contribution

It introduces a novel model for nonlinear transport in anisotropic heterogeneous media, specifically applied to weakly textured MgB2 superconductors.

Findings

The model accurately predicts the field and angular dependence of critical currents.

Preparation methods induce significant macroscopic anisotropy in MgB2.

Theoretical results match experimental data for various textures.

Abstract

A model for highly non-linear transport in heterogeneous media consisting of anisotropic particles with a preferred orientation is proposed and applied to the current transport in weakly textured magnesium diboride, MgB2. It essentially explains why, unlike in conventional superconductors, a significant macroscopic anisotropy of the critical currents can be induced by the preparation of MgB2 tapes. The field and angular dependence of the critical current is calculated for various degrees of texture and compared to experimental data.