Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 100: Frustrated Magnets - Pyrochlore Oxides
TT 100.2: Vortrag
Donnerstag, 15. März 2018, 15:45–16:00, H 3005
The Magnetic Excitations in the Ground State of Yb2Ti2O7 — •Viviane Peçanha-Antonio1,2, Erxi Feng1, Yixi Su1, Franz Demmel3, and Thomas Brückel1,4 — 1Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, D-85747 Garching, Germany — 2Physik-Department, Technische Universität München, D-85747 Garching, Germany — 3ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom — 4Jülich Centre for Neutron Science (JCNS) and Peter Grünberg Institut (PGI), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
The nature of the zero-field ground state of Yb2Ti2O7 remains an enigma within the pyrochlore titanate series. The disparate results are attributed to subtle changes in the sample stoichiometry, which seems to tune the magnetic order of different samples across a phase boundary. We report a study on the zero-field ground state of a powder sample of this pyrochlore. A sharp heat capacity anomaly at Tc= 280 mK is accompanied by a quasicollinear ferromagnetic order with a magnetic moment of 0.87(2)µB. Our high-resolution inelastic neutron scattering measurements show that, upon cooling, an inelastic continuum of excitations at ∼0.6 is observed to persist from at least 2.5 K down to the lowest reached temperatures. Below Tc, the coexistence of sharp gapped low-energy magnetic excitations with a remnant quasielastic contribution evidences that spin fluctuations persist despite the long-range magnetic order.