Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 100: Frustrated Magnets - Pyrochlore Oxides

TT 100.7: Vortrag

Donnerstag, 15. März 2018, 17:15–17:30, H 3005

Features of quantum spin ice in pyrochlore Nd₂Zr₂O₇ — •Jianhui Xu^1,2, A. T. M. Nazmul Islam¹, Owen Benton³, Georg Ehlers⁴, and Bella Lake^1,2 — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany — ²Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany — ³RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan — ⁴Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA

Magnetic pyrochlore oxides are intensively studied in the field of frustrated magnetism and the pyrochlores with Ising-anisotropic light rare earth are candidates for quantum spin ice. The recent studies on Nd₂Zr₂O₇ show that the single-ion ground state of Nd³⁺ is a well-isolated Kramers doublet with Ising anisotropy and the collective ground state is an antiferromagnetic order. Inelastic neutron scattering shows magnetic excitations containing a flat gapped ice-like mode and dispersive branches. The analyses based on spin wave theory indicate quantum moment fragmentation and yield a pseudospin-1/2 Hamiltonian which suggests quantum spin ice state above the ordering temperature (0.4K). Here we show that the extracted spin Hamiltonian gives a qualitative description of the macroscopic properties of Nd₂Zr₂O₇ based on mean-field and Monte Carlo simulations. We also present single-crystal inelastic neutron scattering data above T_N at 450mK and compare with the calculated spinon scattering.