Anisotropy and crystallite misalignment in textured superconductors

TL;DR

This study investigates how crystallite misalignment affects anisotropy and critical current density in textured superconductors, using magnetic measurements and microscopy to relate orientation distributions to magnetic properties.

Contribution

It introduces a method to determine the distribution of crystallite orientations and magnetic disorder angles from magnetization data in textured polycrystalline superconductors.

Findings

Crystallite misalignment reduces anisotropy and critical current density.

Magnetization data can determine orientation distribution and disorder angles.

The method applies to analyzing textured superconductor properties.

Abstract

A misalignment of anisotropic crystallites causes small values of anisotropy and decreases the critical current density of textured polycrystalline superconductors. To relate the crystallite misalignment and out-plane anisotropy, the magnetic properties of the textured Bi2223 polycrystalline superconductor were investigated. A distribution of orientation angles of crystallites was determined using different data: scanning electron microscopy images and hysteresis magnetization loops when an external magnetic field was applied at different angles with respect to the texturing plane of the sample. It was demonstrated that the standard deviation of the distribution and the magnetic disorder angle of crystallites in textured samples can be determined from the magnetization data in perpendicular directions. These data may be either the irreversible magnetization measured for two different orientations of the sample or the simultaneously measured magnetization projections parallel and perpendicular to the magnetic field.