Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 12: Correlated Electrons: Frustrated Magnets - General 1
TT 12.3: Vortrag
Montag, 20. März 2017, 15:30–15:45, HSZ 03
Magnetic resonance as a local probe for S=1/2 Kagomé magnetism in Barlowite Cu4(OH)6FBr — •Ranjith Kumar Kizhake Malayil1, Christian Klein2, Cornelius Krellner2, and Michael Baenitz1 — 1MPI for Chemical Physics of Solids, 01187 Dresden, Germany — 2Institute of Physics, Goethe-University Frankfurt, 60438 Frankfurt am Main, Germany
S=1/2-quantum magnets with Kagomé 2D layer building blocks could serve as model systems for 2D magnetic frustration and may host the quantum spin liquid state (QSL). So far Herbertsmithite (HS) ZnCu3(OH)6Cl2 is the leading candidate for this research, but here structural disorder has some influence on the QSL state. Barlowite, Cu4(OH)6FBr is a relative to HS and is predicted to host an undistorted Kagomé lattice [1].
Here, we present 1H, 19F, and 79,81Br NMR measurements together with a Br-NQR study on polycrystalline samples to probe the magnetism, the magneto elastic coupling and the local disorder. From spin-lattice relaxation results strong evidence for magnetic order at 15 K is given. Furthermore, a large field dependence of the hyperfine fields is observed. This is discussed to originate from a weak out of plane magnetic exchange interaction.
[1] Han et al., Phys. Rev. Lett. 113, 227203 (2014).