Suppression of superconductivity by V-doping and possible magnetic order in Sr2VO3FeAs

TL;DR

This study shows that V-doping in Sr2VO3FeAs suppresses superconductivity and reveals incommensurate magnetic order of vanadium, highlighting the material's sensitivity to Fe/V mixing and intrinsic inhomogeneity.

Contribution

It demonstrates the complete suppression of superconductivity by V-doping and uncovers magnetic ordering in Sr2VO3FeAs, providing insights into the effects of doping and magnetic interactions.

Findings

Superconductivity is suppressed by small V-doping levels.

Incommensurate magnetic order of V-sublattice observed at 4 K.

Sr2VO3FeAs is highly sensitive to Fe/V mixing affecting superconductivity.

Abstract

Superconductivity at 33 K in Sr2VO3FeAs is completely suppressed by small amounts of V-doping in Sr2VO3[Fe0.93(+/-0.01)V0.07(+/-0.01)]As. The crystal structures and exact stoichiometries are determined by combined neutron- and x-ray powder diffraction. Sr2VO3FeAs is shown to be very sensitive to Fe/V mixing, which interferes with or even suppresses superconductivity. This inhomogeneity may be intrinsic and explains scattered reports regarding Tc and reduced superconducting phase fractions in Sr2VO3FeAs. Neutron diffraction data collected at 4 K indicates incommensurate mag- netic ordering of the V-sublattice with a propagation vector q = (0,0,0.306). This suggests strongly correlated vanadium, which does not contribute significantly to the Fermi surface of Sr2VO3FeAs.