Josephson junction between anisotropic superconductors

TL;DR

This paper derives a generalized sine-Gordon equation for Josephson junctions with anisotropic superconductors and analyzes the resulting vortex behavior and mechanical torque effects related to crystal orientation.

Contribution

It introduces a new theoretical framework for Josephson junctions with anisotropic banks and explores vortex dynamics and torque in twinned crystal structures.

Findings

Derived the sine-Gordon equation for anisotropic Josephson junctions

Analyzed Josephson vortex behavior at twin planes in YBCO-like materials

Predicted measurable mechanical torque depending on vortex orientation

Abstract

The sin-Gordon equation for Josephson junctions with arbitrary misaligned anisotropic banks is derived. As an application, the problem of Josephson vortices at twin planes of a YBCO-like material is considered. It is shown that for an arbitrary orientation of these vortices relative to the crystal axes of the banks, the junctions should experience a mechanical torque which is evaluated. This torque and its angular dependence may, in principle, be measured in small fields, since the flux penetration into twinned crystals begins with nucleation of Josephson vortices at twin planes.