Complex Chiral Modulations in FeGe close to Magnetic Ordering

TL;DR

This study uses polarized small-angle neutron scattering to investigate complex chiral magnetic modulations in FeGe near its magnetic ordering, revealing detailed phase diagrams and unique scattering patterns across different magnetic field orientations.

Contribution

It provides new insights into the magnetic phase structure of FeGe, identifying a segmented A-phase and distinct scattering behaviors in different geometries.

Findings

Segmented A-phase region identified below magnetic order.

Hexagonal Bragg-spot patterns observed in the A-phase.

Distinct scattering intensity variations in different geometries.

Abstract

We report on detailed polarized small-angle neutron scattering on cubic FeGe in magnetic fields applied either along (transverse) the scattering vector or parallel (longitudinal)to the neutron beam. The ($H,T$) phase diagrams for all principal axes contain a segmented $A$-phase region just below the onset of magnetic order. Hexagonal Bragg-spot patterns were observed across the entire $A$-phase region for the longitudinal geometry. Scattering intensity was observed in parts of the A phase for both scattering configurations. Only in a distinct pocket ($A_1$) vanishing scattering intensity was found in the transverse geometry.