Strong enhancement of critical current density in both low & high fields and flux pinning mechanism under hydrostatic pressure in optimally doped (Ba,K)Fe2As2 single crystals

TL;DR

Applying hydrostatic pressure up to 1.2 GPa on optimally doped Ba0.6K0.4Fe2As2 crystals significantly enhances flux pinning and critical current density across various magnetic fields by increasing defect density and pinning force.

Contribution

This study demonstrates that hydrostatic pressure effectively boosts flux pinning and critical current density in Ba0.6K0.4Fe2As2, revealing a new method to improve superconductor performance.

Findings

Critical current density increased by up to 5 times under pressure.

Both pinning center density and force are significantly enhanced.

Flux pinning mechanism is improved by hydrostatic pressure.

Abstract

Strong pinning depends on the pinning force strength and number density of effective defects. Using hydrostatic pressure method, we demonstrate that hydrostatic pressure up to 1.2 GPa can significantly enhance flux pinning or Jc by a factor of up to 5 especially in both low and high fields in optimally doped Ba0.6K0.4Fe2As2 crystals. Our analysis on the flux pining mechanism indicate that both pinning centre number density (Np) and pinning force (Fp) are greatly increased by the pressure and contribute to strong pinning.