On the robustness of the MnSi magnetic structure determined by muon spin rotation

TL;DR

This study confirms the robustness of MnSi's magnetic structure determined by muSR, demonstrating consistency across different crystal growth methods and ruling out muon-induced effects, thus validating previous findings about its magnetic phases.

Contribution

The paper provides experimental validation and simulation support for the previously proposed magnetic structures of MnSi, highlighting the complementarity of muSR and neutron scattering techniques.

Findings

Magnetic structures are consistent across different crystal growth methods.

Muon-induced effects are ruled out as influencing the magnetic structure.

Simulations confirm the uniqueness of the initial muSR interpretation.

Abstract

Muon spin rotation (muSR) spectra recorded for manganese silicide MnSi and interpreted in terms of a quantitative analysis constrained by symmetry arguments were recently published. The magnetic structures of MnSi in zero-field at low temperature and in the conical phase near the magnetic phase transition were shown to substantially deviate from the expected helical and conical structures. Here, we present material backing the previous results obtained in zero-field. First, from simulations of the field distributions experienced by the muons as a function of relevant parameters we confirm the uniqueness of the initial interpretation and illustrate the remarkable complementarity of neutron scattering and muSR for the MnSi magnetic structure determination. Second we present the result of a muSR experiment performed on MnSi crystallites grown in a Zn-flux and compare it with the previous data recorded with a crystal obtained from Czochralski pulling. We find the magnetic structure for the two types of crystals to be identical within experimental uncertainties. We finally address the question of a possible muon-induced effect by presenting transverse field muSR spectra recorded in a wide range of temperature and field intensity. The field distribution parameters perfectly scale with the macroscopic magnetization, ruling out a muon-induced effect.