Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 41: Frustrated Magnets - Spin Liquids - Experiments

TT 41.6: Vortrag

Dienstag, 13. März 2018, 11:45–12:00, H 3005

Frozen state and spin-gap behavior in a new kagome magnet Fe₄Si₂Sn₇O₁₆: An NMR study — •S. Dengre¹, R. Sarkar¹, M.C. Allision^{2, 3}, T. Söhnel², C.D. Ling³, J. Gardner⁴, and H.-H. Klauss¹ — ¹Institute of Solid State and Materials Physics, TU Dresden, 01062 Dresden, Germany — ²School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand — ³School of Chemistry, The University of Sydney, Sydney 2006, Australia — ⁴Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organization, Menai 2234, Australia

Fe₄Si₂Sn₇O₁₆ is a new Fe based kagome system with a f=θ/T_N≈3.6. The system consists of alternate stacking of kagome layer formed from edge sharing FeO₆ (S = 2) and SnO₆ octahedra and stannate layer FeSn₆ (S = 0). Fe₄Si₂Sn₇O₁₆ is a classical homologue to a famous kagome compound herbertsmithite, a suitable candidate to realize quanum spin liquid phase. ^(117/119)Sn nuclear magnetic resonance (NMR) allows us to selectively probe the static and dynamic magnetism of different Fe-layers. While the NMR shift vs bulk susceptibility plot follows linear relation down to 10 K confirming the absence of foreign phases in the vicinity of kagome plane, the considerable line broadening below 10 K indicates the distribution of static internal field. NMR spin-lattice/spin relaxation rate (1/T₁)/(1/T₂) reflect the slowing down of spin fluctuations at ∼3 K associated with the static magnetism of Fe-kagome layer. Additionally, (1/T₁) and (1/T₂) temperature dependency show a spin-gap behavior with Δ∼6.5 K.
Ling et al. Phys. Rev. B 96, 180410(R).