Dresden 2017 – wissenschaftliches Programm
MA 44.5: Vortrag
Mittwoch, 22. März 2017, 16:00–16:15, HSZ 403
Evidence for possible quantum spin-ice behaviour in Pr2Hf2O7 as seen by inelastic neutron scattering. — •Alexandros Samartzis1, Vivek K. Anand1, Nazmul A.T.M. Islam1, Andrew Wildes2, Robert Bewley3, Andrey A. Podlesnyak4, David Voneshen3, and Bella Lake1 — 1Helmholtz-Zentrum Berlin, Germany — 2Institute Laue-Langevin, France — 3Rutherford Appleton Lab, UK — 4Oak Ridge, National Lab, US
The rare earth pyrochlore systems are well known for their diverse magnetic ground state due to quintenssential lattice for frustration and Ising anisotropy. A delicate competition of crystal field, exchange and dipolar interactions can lead to exotic magnetic ground states, such as spin-ice. Pr-based pyrochlores are candidates of a new ground state named, quantum spin-ice, due to low magnetic moment of the non-Kramers Pr3+ ion. Recently, the low temperature macroscopic measurements of Pr2Hf2O7 as well as inelastic neutron scattering (INS) of powder sample have shown evidence for the realization of quantum spin-ice behavior (i.e. quantum fluctuations and slow spin-dynamics in the ground state etc). Motivated by the above interesting results, we extended the study using polarised and low energy neutron scattering with and without external field on a PHO single crystal, grown by the floating zone technique. The first results reveal the absence of any transition down to 85mK. Broad diffuse scattering and pinch points indicate increased quantum fluctuations. Inelastic data reveal a broad dispersionless magnetic excitation, with a narrow band gap which shifts to higher transferred energies by an applied field.