Low-temperature Synthesis of FeTe0.5Se0.5 Polycrystals with a High Transport Critical Current Density

TL;DR

This study demonstrates a low-temperature synthesis method for FeTe0.5Se0.5 polycrystals that achieve high critical current densities and upper critical fields, comparable to single crystals, improving superconducting wire performance.

Contribution

The paper introduces a low-temperature synthesis process for FeTe0.5Se0.5 polycrystals with high transport critical current density and critical fields, enhancing superconducting wire applications.

Findings

Critical current density over 700 A/cm2 at 4.2 K

Upper critical field of 585 kOe at 0 K

Polycrystals comparable to single crystals in performance

Abstract

We have prepared high-quality polycrystalline FeTe0.5Se0.5 at temperature as low as 550{\deg}C. The transport critical current density evaluated by the current-voltage characteristics is over 700 A/cm2 at 4.2 K under zero field, which is several times larger than FeTe0.5Se0.5 superconducting wires. The critical current density estimated from magneto-optical images of flux penetration is also similar to this value. The upper critical field of the polycrystalline FeTe0.5Se0.5 at T = 0 K estimated by Werthamer-Helfand-Hohenberg theory is 585 kOe, which is comparable to that of single crystals. This study gives some insight into how to improve the performance of FeTe0.5Se0.5 superconducting wires.