Effects of the sintering atmosphere on the superconductivity of SmFeAsO1-xFx compounds

TL;DR

This study investigates how different sintering atmospheres affect the superconducting properties of SmFeAsO1-xFx compounds, revealing that oxygen presence and fluorine loss significantly influence the transition temperature.

Contribution

It systematically examines the impact of sintering atmosphere pressure on superconductivity and elucidates fluorine loss mechanisms affecting Tc in SmFeAsO1-xFx.

Findings

Tc remains near 50 K until oxygen concentration exceeds a threshold

Fluorine loss due to vaporization and reactions reduces superconductivity

Oxygen in the sintering atmosphere has detrimental effects

Abstract

A series of SmFeAsO1-xFx samples were sintered in quartz tubes filled with air of different pressures. The effects of the sintering atmosphere on the superconductivity were systematically investigated. The SmFeAsO1-xFx system maintains a transition temperature (Tc) near 50 K until the concentration of oxygen in quartz tubes increases to a certain threshold, after which Tc decreases dramatically. Fluorine losses, whether due to vaporization, reactions with starting materials, and reactions with oxygen, proved to be detrimental to the superconductivity of this material. The deleterious effects of the oxygen in the sintering atmosphere were also discussed in detail.