Evolution of tetragonal phase in the FeSe wire fabricated by a novel chemical-transformation PIT process

TL;DR

This paper reports on the fabrication of superconducting FeSe wires using a novel chemical-transformation PIT process, highlighting how annealing temperature influences phase transformation and enhances superconducting properties.

Contribution

It introduces a new chemical-transformation PIT method for FeSe wire fabrication and demonstrates the phase evolution and property improvements with annealing temperature.

Findings

Annealing above 500°C induces phase transformation from hexagonal to tetragonal.

Complete transformation to tetragonal phase occurs at 1000°C.

Superconducting properties improve significantly with increased annealing temperature.

Abstract

We fabricated superconducting FeSe wires by the chemical-transformation PIT process. The obvious correlation between annealing temperature and phase transformation was observed. Annealing above 500^{\circ}C produced wire-core transformation from hexagonal to tetragonal phase. Furthermore the hexagonal phase completely transformed into the tetragonal phase by annealing at 1000^{\circ}C. With increasing annealing temperature, the superconducting property was dramatically improved, associated with the evolution of the tetragonal phase.