Upper critical fields and critical current density of BaFe2(As0.68P0.32)2 single crystal

TL;DR

This study investigates the superconducting properties of BaFe2(As0.68P0.32)2 single crystals, revealing high upper critical fields, low anisotropy, and moderate critical current density, contributing valuable data for understanding iron-based superconductors.

Contribution

It provides detailed measurements of critical fields, anisotropy, and current density in phosphorus-doped BaFe2As2, highlighting their superconducting characteristics near optimal doping.

Findings

Upper critical field Hc2^ab exceeds 77 Tesla

Superconducting anisotropy ratio is approximately 2

Critical current density reaches 10^5 A/cm2 at 5 K

Abstract

The transport properties, upper critical fields, superconducting anisotropy, and critical current density in an iso-valent phosphorus-doped BaFe2As2 single crystal close to optimum doping are investigated in this report. Temperature dependent resistivity and susceptibility show a superconducting transition temperature, Tc, just below 31 K both with sharp transitions. The upper critical field parallel to the ab-plane, Hc2^ab, is above 77 Tesla while that along the c-axis direction, Hc2^c, is just above 36 Tesla, yielding a low superconducting anisotropy ratio ~ 2. The estimated inter-plane coherence length based on the Ginzburg-Landau (G-L) theory indicates BaFe2(As0.68P0.32)2 is still above the point for a dimensional crossover inferring the superconducting layers are not weakly-coupled in this system. The critical current density at 5 K obtained from magnetization loops measurement show a modest Jc as high as 10^5 A/cm2.