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SUMMARY:Phase diagram and spin dynamics of the  frustrated pyrochlore magn
 et   Yb2Ti2O7 in applied field - Paul McClarty\, Wadham College\, Universi
 ty of Oxford. Science &amp\; Technology Facilities Council.
DTSTART:20161123T111500Z
DTEND:20161123T121500Z
UID:TALK68881@talks.cam.ac.uk
CONTACT:Helen Verrechia
DESCRIPTION:The frustrated pyrochlore magnet Yb2Ti2O7 has been proposed as
  a candidate ""quantum spin ice" material. Here we report extensive inelas
 tic neutron scattering measurements of the spin dynamics and complementary
  specific heat measurements to map the phase diagram in magnetic field app
 lied along the cubic [001] direction *\, not explored experimentally in de
 tail before. The high quality of our single crystals is evidenced by a sha
 rp zero-field anomaly near 220 mK. We characterize how the spin excitation
 s evolve gradually from very high applied magnetic fields (9 T) when one-m
 agnon excitations dominate\, all the way down to zero field where the spec
 trum is replaced by a scattering continuum extended over a broad energy ra
 nge. Through fits of the dispersion relations at high field we propose a r
 e-evaluation of the spin Hamiltonian to consistently explain all existing 
 spin dynamics data for different field directions and propose a phenomenol
 ogical model of the evolution of the spin dynamics in applied field.      
  \n\n* J. D. Thompson\, P. McClarty\, D. Prabhakaran\, I. Cabrera\, T. Gui
 di and R. Coldea\, (in preparation)\n
LOCATION:Mott Seminar Room (531)\, Cavendish Laboratory\, Department of Ph
 ysics
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