Pressure induced magnetic order in FeSe

TL;DR

This study investigates how applying pressure induces magnetic order in FeSe, revealing possible magnetic structures and quantifying the magnetic moment per Fe atom using muon-spin rotation techniques.

Contribution

It provides the first detailed analysis of pressure-induced magnetic order in FeSe, identifying its possible magnetic configurations and measuring the magnetic moment.

Findings

Pressure induces magnetic order in FeSe.

Magnetic order resembles collinear or Bi-Collinear antiferromagnetic structures.

Magnetic moment per Fe atom is approximately 0.13-0.14 μB at 1.9 GPa.

Abstract

The magnetic order induced by the pressure was studied in single crystalline FeSe by means of muon-spin rotation ($\mu$SR) technique. By following the evolution of the oscillatory part of the $\mu$SR signal as a function of angle between the initial muon-spin polarization and 101 axis of studied crystal it was found that the pressure induced magnetic order in FeSe corresponds either to the collinear (single-stripe) antiferromagnetic order as observed in parent compounds of various FeAs-based superconductors or to the Bi-Collinear order as obtained in FeTe system, but with the Fe spins turned by 45$^{\rm o}$. The value of the magnetic moment per Fe atom was estimated to be $\simeq 0.13-0.14$~$\mu_{\rm B}$ at $p\simeq 1.9$~GPa.