Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 100: Frustrated Magnets - Pyrochlore Oxides
TT 100.3: Vortrag
Donnerstag, 15. März 2018, 16:00–16:15, H 3005
Spin dynamics in the spin ice Ho2Ti2O7 as measured by MIEZE spectroscopy — •Andreas Wendl1, S. Säubert1,2, C. Franz2, P. Dharmalingam3, A. Boothroyd3, and C. Pfleiderer1 — 1Technische Universität München, Garching, Germany — 2Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany — 3Clarendon Laboratory, University of Oxford, United Kingdom
In the cubic rare-earth pyrochlore Ho2Ti2O7 the combination of a tetrahedral Ho-atom sub-lattice with strong local Ising anisotropies leads to a spin arrangement satisfying the spin ice rules at low temperatures [1]. At high temperatures the combination of crystal fields and phononic states creates rich physics: Thermally driven transitions of the ground state doublet deviate from an Arrhenius law [2] as phonon mediated spin-flipping becomes relevant[3]. Furthermore, crystal field transitions between excited states appear once these states are populated at sufficient temperatures [3,4].
We report a study of the high temperature spin flip excitations in Ho2Ti2O7 employing the high-resolution neutron spin echo technique MIEZE. Our measurements provide unprecedented information on the spin dynamics measured over five magnitudes in time, thus allowing to close the gap between TAS [2,3] and NSE [2], and extending it towards lower momentum transfers. Our results agree with refs [2-4] and further confirm the single ion character of spin fluctuations.
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