Split of the magnetic and crystallographic states in Fe$_{1-x}$Rh$_{x}$Ge

TL;DR

This study investigates Fe$_{1-x}$Rh$_{x}$Ge compounds across all compositions, revealing an internal splitting of crystallographic and magnetic states within single crystallites, with distinct magnetic structures despite shared space groups.

Contribution

It provides the first comprehensive experimental and theoretical analysis of phase splitting in Fe$_{1-x}$Rh$_{x}$Ge, highlighting the coexistence of different magnetic states within the same crystallographic phase.

Findings

Internal splitting of crystallographic and magnetic states in intermediate compositions.

Different magnetic structures (ferro- and helimagnetic) coexist within the same phase.

Splitting occurs within single crystallites, preserving the space group.

Abstract

We report on a comprehensive experimental and theoretical study of Fe$_{1-x}$Rh$_{x}$Ge compounds, within the entire concentration range $x \in \left[0.0 - 1.0\right]$, using X-Ray diffraction, small-angle neutron scattering, magnetometry and theoretical calculations. While FeGe and RhGe are single phase helimagnet and unconventional superconductor, respectively, an internal splitting of the crystallographic and magnetic states is found for intermediate compositions $x \in \left[0.2 - 0.9\right]$. A theoretical analysis of the stability of the two detected phases, together with the experimental data, indicate that this splitting preserves a common space group and occurs within single crystallites. Despite their apparent similarity, these two phases however display different magnetic structures, with distinct ferro- and helimagnetic character.