Chemomagnetism, magnetoconcentration effect and "fishtail" anomaly in chemically-induced granular superconductors

TL;DR

This paper predicts novel magnetic effects in granular high-T_c superconductors caused by chemical modifications, including chemomagnetism and a fishtail-like magnetization anomaly, based on a 2D Josephson junction array model.

Contribution

It introduces a 2D Josephson junction array model to describe chemically-induced magnetic phenomena in granular superconductors, predicting effects not previously documented.

Findings

Prediction of Josephson chemomagnetism and its impact on low-field magnetization.

Identification of a magnetoconcentration effect influencing high-field magnetization.

Proposal of experimental conditions for observing these effects in non-stoichiometric high-T_c superconductors.

Abstract

Within a 2D model of Josephson junction arrays (created by 2D network of twin boundary dislocations with strain fields acting as insulating barrier between hole-rich domains in underdoped crystals), a few novel effects expected to occur in intrinsically granular material are predicted including: (i) Josephson chemomagnetism (chemically induced magnetic moment in zero applied magnetic field) and its influence on a low-field magnetization (chemically induced paramagnetic Meissner effect), and (ii) magnetoconcentration effect (creation of oxygen vacancies in applied magnetic field) and its influence on a high-field magnetization (chemically induced analog of "fishtail" anomaly). The conditions under which these effects can be experimentally measured in non-stoichiometric high-T_c superconductors are discussed.