Current density and reversible magnetization of HgBa(2)Ca(2)Cu(3)O(x) superconductors containing randomly oriented columnar defects

TL;DR

This study investigates how proton-induced columnar defects affect the magnetic properties and current density in HgBa(2)Ca(2)Cu(3)O(x) superconductors, revealing the interplay between defects and superconducting behavior.

Contribution

It introduces a method to create randomly oriented columnar defects in Hg-based superconductors and analyzes their impact on magnetization and current density.

Findings

Increased defect density enhances vortex pinning.

Magnetization behavior aligns with London theory including vortex-defect interactions.

Reversible magnetization and current density depend on defect density and temperature.

Abstract

Bulk polycrystalline HgBa(2)Ca(2)Cu(3)O(x) materials were irradiated with 0.8 GeV protons to form randomly oriented columnar defects, by induced fission of Hg-nuclei. Proton fluences from 0 to 35 times 10^{16} cm^{-2} were used to install defects with area densities up to a "matching field" of 3.4 Tesla. Studies were conducted on the dependence of the equilibrium magnetization and the intragrain persistent current density on temperature and applied magnetic field, at various defect densities. The magnetization was modeled using London theory with the addition of vortex-defect interactions.