Critical Current Density and AC Magnetic Susceptibility of High-quality FeTe$_{0.5}$Se$_{0.5}$ Superconducting Tapes

TL;DR

This study investigates FeTe$_{0.5}$Se$_{0.5}$ superconducting tapes, demonstrating high critical current density, strong flux pinning, and homogeneous superconductivity, indicating their potential for high-field applications.

Contribution

The paper reports the fabrication and comprehensive characterization of FeTe$_{0.5}$Se$_{0.5}$ superconducting tapes with high critical current density and effective flux pinning, advancing their practical application prospects.

Findings

Critical current density exceeds 10^5 A/cm^2 at 8 K and 9 T.

Normal point pinning is identified as the dominant flux pinning mechanism.

Tapes exhibit homogeneous superconductivity and strong flux pinning under high magnetic fields.

Abstract

Iron telluride-selenium superconducting materials, known for their non-toxicity, ease of preparation, simple structure, and high upper critical fields, have attracted much research interest in practical application. In this work, we conducted electrical transport measurements, magneto-optical imaging, and AC magnetic susceptibility measurements on FeTe$_{0.5}$Se$_{0.5}$ superconducting long tapes fabricated via reel-to-reel pulsed laser deposition. Our transport measurements revealed a high critical current density that remains relatively stable even with increasing external magnetic fields, reaching over $1\times 10^5$ A/cm$^2$ at 8 K and 9 T. The calculated pinning force density indicates that normal point pinning is the primary mechanism in these tapes. The magneto-optical images demonstrated that the tapes show homogeneous superconductivity and uniform distribution of critical current density. The AC magnetic susceptibility measurements also confirmed their strong flux pinning nature of withstanding high magnetic field. Based on these characteristics, FeTe$_{0.5}$Se$_{0.5}$ superconducting tapes show promising prospects for applications under high magnetic fields.