Chemically Induced Nanoscale Josephson Effects in Non-Stoichiometric High-Temperature Superconductors

TL;DR

This paper explores novel nanoscale Josephson effects in non-stoichiometric high-temperature superconductors, focusing on chemically induced magnetic and electric phenomena in granular materials modeled by 2D Josephson junction arrays.

Contribution

It introduces theoretical predictions of chemically induced magnetization, charge effects, and anomalies in high-temperature superconductors with granular structures.

Findings

Prediction of chemomagnetism and its influence on low-field magnetization.

Identification of charge-related effects like chemomagnetoelectricity and magnetocapacitance.

Observation of field-dependent weakening of Coulomb blockade in these materials.

Abstract

This paper reviews some of the recently suggested (by the author) novel effects expected to occur in intrinsically granular non-stoichiometric material modeled by 2D Josephson junction arrays which are created by a regular 2D network of twin-boundary dislocations with strain fields acting as an insulating barrier between hole-rich domains in underdoped crystals. In Section 2 we consider phase-related magnetization effects, including Josephson chemomagnetism (chemically induced magnetic moment in zero applied magnetic field) and its influence on a low-field magnetization (chemically induced PME), and magnetoconcentration effect (creation of extra oxygen vacancies in applied magnetic field) and its influence on a high-field magnetization (chemically induced analog of "fishtail" anomaly). Section 3 addresses charge-related phenomena which are actually dual to the chemomagnetic effects described in Section 2. More specifically, we discuss a possible existence of a non-zero electric polarization (chemomagnetoelectic effect) and the related change of the charge balance in intrinsically granular non-stoichiometric material under the influence of an applied magnetic field. In particular, we predict an anomalous low-field magnetic behavior of the effective junction charge and concomitant magnetocapacitance in paramagnetic Meissner phase and a charge analog of "fishtail" anomaly at high magnetic fields as well as field-dependent weakening of the chemically-induced Coulomb blockade.