Conference Presentation (Invited)

FZJ-2024-06886

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Magnetic Fluctuations in FeSi

Pfleiderer, C. ; Schmalzl, K.FZJ* ; Beddrich, L.FZJ* ; Skoulatos, M. ; Tang, R. ; Georgii, R. ; Raymond, S. ; Schmidt, W.FZJ* ; Du, Y.

2024

Abstract: Our research focuses on the magnetic properties of FeSi, particularly investigating the potentialpresence of magnetic chirality through neutron spin-dependent scattering experiments. FeSi, whichcrystallizes in the P213 space group, shows a distinct increase in bulk magnetic susceptibility withtemperature, peaking around T = 500 K. Despite this, it exhibits no long-range magnetic order acrossthe entire temperature range. However, magnetic fluctuations are observed at ambient and highertemperatures. This study expands on previous work exploring the magnetic behaviour of FeSi andthe related compound MnSi, which also belongs to the P213 space group. MnSi has been shown todemonstrate a skyrmion lattice phase, a unique magnetic state with chiral fluctuations, which weaim to compare with FeSi.Using polarized neutron beams and xyz-polarization analysis on the IN12 triple-axis spectrometer,we conducted a detailed examination of the magnetic fluctuations in FeSi. We aimed to determinewhether chiral magnetic scattering is an intrinsic feature of crystals with the B20 structure, a crystalstructure known for its non-centrosymmetric properties. We measured the differences in neutronscattering intensities for distinct spin configurations and applied flipping ratio corrections to enhancethe accuracy of our results. While magnetic fluctuations were observed, the analysis showedonly a small chiral component, suggesting that chirality is not a pervasive magnetic feature in FeSi,unlike in MnSi.Our findings’ comparison with the magnetic fluctuations in MnSi provides insights into FeSi’s magneticbehaviour that could have a significant impact on the scientific community. It may help explainthe enhancement of the topological Hall effect observed in Mn(1-x)Fe(x)Si alloys. These results contributeto understanding the complex magnetic ground states in materials with non-centrosymmetriccrystal structures.20

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Contributing Institute(s):

1. Streumethoden (JCNS-2)
2. JARA-FIT (JARA-FIT)
3. JCNS-4 (JCNS-4)
4. JCNS-ILL (JCNS-ILL)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ) (POF4-6G4) (POF4-6G4)

Experiment(s):

1. ILL-IN12: Cold neutron 3-axis spectrometer

Appears in the scientific report 2024

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