Increase of critical current density in FeSe superconductor by strain effect

Abstract

Conventional $J_c$-enhancement methods like doping and irradiation often introduce extrinsic elements or defects, altering intrinsic properties. Here, we report a significant $J_c$ enhancement in FeSe single crystals through compressive strain applied using a glass-fiber-reinforced plastic substrate with anisotropic thermal contraction during cooling. Under zero field at 2 K, $J_{\text{c}}$ increases by a factor of $\sim$4 from $\sim 2.3\times 10^4$ to $\sim 8.7\times 10^4$ A cm${}^{-2}$; at 5 T, it achieves an order-of-magnitude enhancement, rising from $\sim 1.0\times 10^3$ to $\sim 1.0\times 10^4$ A cm${}^{-2}$. Analysis based on the Dew-Hughes model of the $f_{\text{p}}$(h) relationship shows that strain strengthens vortex pinning, and shifts the pinning mechanism from point-like pinning to combined point and surface pinnings. This work offers an effective method to enhance FeSe's current-carrying limitation, deepens understanding of iron-based superconductors' pinning mechanisms, and highlights strain engineering's potential for optimizing superconducting performance.

8 pages, 4 figures

References in corpus (13)

• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• The Structural Phase Transition in FeSe (Fe1+dSe)
• Advantageous grain boundaries in iron pnictide superconductors
• Vortex phase diagram of Ba(Fe0.93Co0.07)2As2 single crystals
• High magnetic field scales and critical currents in SmFeAs(O,F) crystals: promising for applications
• Flux pinning in (1111) iron-pnictide superconducting crystals
• Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors
• Effects of heavy-ion irradiation on FeSe
• Critical divergence of the symmetric ($A_{1g}$) nonlinear elastoresistance near the nematic transition in an iron-based superconductor
• Giant enhancement of critical current density at high field in superconducting (Li,Fe)OHFeSe films by Mn doping
• Significant enhancement of critical current density in H+-intercalated FeSe single crystal
• Bulk and surface Dirac states accompanied by two superconducting domes in FeSe-based superconductors
• Effects of 6 MeV proton irradiation on the vortex ensemble in BaFe${}_2$(As${}_{0.67}$P${}_{0.33}$)${}_2$ revealed through magnetization measurements and real-space vortex imaging