Structural and transport properties of Sr2VO{3-delta}FeAs superconductors with different oxygen deficiencies

TL;DR

This study investigates how oxygen deficiency affects the structural, electronic, and superconducting properties of Sr2VO3-deltaFeAs, revealing a decrease in transition temperature and increased scattering with more oxygen vacancies.

Contribution

It provides new insights into the relationship between oxygen deficiency and superconductivity in Sr2VO3-deltaFeAs, including detailed transport and electronic property analysis.

Findings

Superconducting temperature drops with increased oxygen deficiency.

Residual resistivity increases as oxygen deficiency rises.

Charge carrier density varies with oxygen deficiency.

Abstract

Sr2VO{3-delta}FeAs superconductors with different oxygen deficiencies have been successfully fabricated. It is found that the superconducting transition temperature drops down monotonically with the increase of oxygen deficiency. The diminishing of superconductivity is accompanied by the enhancement of residual resistivity, indicating an unraveled scattering effect induced by the oxygen deficiency. The highest superconducting transition temperature at about 40 K is achieved near the stoichiometrical sample Sr$_2$VO$_{3}$FeAs. Surprisingly, the X-ray photoelectron spectroscopy (XPS) shows that the vanadium has a "5+" valence state in the samples. The Hall effect measurements reveal that the density of charge carriers (electron-like here) varies qualitatively with the increase of oxygen deficiency. Magnetotransport measurements show that the superconducting transition changes from one-step-like shape at low fields to two-step-like one at high fields, indicating a high anisotropy.