Dresden 2026 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 95: Fe-based Superconductors

TT 95.7: Vortrag

Freitag, 13. März 2026, 11:15–11:30, HSZ/0103

Inelastic neutron scattering study of magnetic fluctuations in iron germanides YFe₂Ge₂ and LuFe₂Ge₂ — •Ran Tao¹, Jiasheng Chen¹, Stephen Hodgson¹, Philipp Niklowitz², Malte Grosche¹, Travis Williams³, David Voneshen³, Devashibhai Adroja³, Paul Steffens⁴, Alexandre Ivanov⁴, and Andrea Piovano⁴ — ¹Cavendish Laboratory, University of Cambridge, UK — ²Department of Physics, Royal Holloway, University of London, UK — ³ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, UK — ⁴Insitut Laue-Langevin, Grenoble, France

The iron-based superconductor YFe₂Ge₂ (T_c ≃ 1.8 K) exhibits strong electronic correlations [1,2], and a prior neutron scattering study has demonstrated enhanced magnetic fluctuations [3]. The isoelectronic and isostructural sister compound LuFe₂Ge₂ orders antiferromagnetically with Q_F = (0,0,1) below T_N ≃ 6.5 K, and in clean crystals shows a resistive superconducting transition below 1 K.

Our inelastic neutron scattering experiments in YFe₂Ge₂ indicate that the dynamic response near Q_F deviates from the commonly assumed overdamped oscillator form and could instead best be fitted with an underdamped form. A similar response is also seen in the sister compound LuFe₂Ge₂ in the paramagnetic phase. The similarities between the two materials suggest that resonant spin fluctuations may be a more general feature in iron germanides.
[1] J. Chen et al., Phys. Rev. Lett. 125, 237002 (2020).
[2] J. Baglo et al., Phys. Rev. Lett. 129, 046402 (2022).
[3] H. Wo et al., Phys. Rev. Lett. 122, 217003 (2019).

Keywords: Magnetic fluctuations; Superconductivity; Quantum phase transitions