Coupled Magnetic and Superconducting Transitions in Sr$_{2}$VO$_{3}$FeAs Under Pressure

TL;DR

This study investigates how pressure influences magnetic and superconducting transitions in Sr$_{2}$VO$_{3}$FeAs, revealing a cooperative relationship where static V magnetism appears essential for superconductivity.

Contribution

It demonstrates the pressure-dependent interplay between magnetic order and superconductivity, highlighting the role of V 3d state localization in enabling superconductivity.

Findings

$T_{N}$ decreases then increases with pressure

$T_{c}$ increases with pressure

Magnetism is a prerequisite for superconductivity

Abstract

We report muon spin rotation ($\mu$SR) and magnetization measurements on superconducting Sr$_{2}$VO$_{3}$FeAs under pressure. At ambient pressure, Sr$_{2}$VO$_{3}$FeAs undergoes an antiferromagnetic transition of the V moments at $T_{N}$ and becomes superconducting at $T_{c}<T_{N}$. As a function of pressure, $T_{N}$ initially decreases while $T_{c}$ increases. Surprisingly, once $T_{N}\approx T_{c}$ at 0.6~GPa, $T_{N}$ reverses its trend and increases together with $T_{c}$ suggesting that the static V magnetism is a prerequisite for superconductivity. We explain this cooperative coupling by a possible localization of the V 3$d$ states below the magnetic transition which enables the nesting of the Fermi surface necessary for superconductivity.