Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 78: Correlated Electrons: Poster Session

TT 78.23: Poster

Donnerstag, 10. März 2016, 15:00–18:30, Poster D

Coexistence of spin frozen state and persistent spin dynamics in NaSrCo₂F₇ as probed by µSR and NMR — •Shanu Dengre¹, Rajib Sarkar¹, Sascha Albert Bräuninger¹, Jason W. Krizan², Felix Brückner¹, Philipp Materne¹, Hubertus Luetkens³, Chris Baines³, Hans-Henning Klauss¹, and Robert J. Cava² — ¹Institute for Solid State Physics, TU Dresden, D-01069, Germany — ²Department of Chemistry, Princeton University, Princeton, NJ 08544, USA — ³Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen, Switzerland

²³Na -and ¹⁹F NMR, and µSR experiments are performed to explore the microscopic properties of NaSrCo₂F₇, which is a newly discovered magnetically frustrated pyrochlore with weak bond disorder and with a frustration index of f = 42. While ²³Na and ¹⁹F NMR experiments clearly suggest the presence of quasi static field distribution below ∼3 K as reflected in the huge NMR line broadening and wipe out effect of NMR signal intensity, µSR experiments on the other hand remains passive to this spin frozen state. Both NMR and µSR results indicate the slowing down of the magnetic (spin) fluctuations upon cooling towards the NMR spin frozen state. µSR relaxation rate increases slightly below ∼ 3 K, and remains not only constant down to 20 mK, but also stands independent in longitudinal magnetic field upto 4000 G implying that the spin fluctuations are dynamic. These observations suggest the coexistence of partial spin frozen state and persistent spin dynamics in NaSrCo₂F₇.