Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 28: Magnetic Materials
MA 28.11: Vortrag
Mittwoch, 13. März 2013, 17:45–18:00, H22
Investigation on magnetoacoustic properties of spin-ice materials Dy2Ti2O7 and Ho2Ti2O7 — •Salim Erfanifam1, Sergei Zherlitsyn1, Joachim Wosnitza1, Roderich Moessner2, Andrei Anatolievich Zvyagin2,3, Paul McClarty2, Oleg Petrenko4, and Geetha Balakrishnan4 — 1Hochfeld-Magnetlabor Dresden, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany — 2Max-Planck Institut für Physik komplexer Systeme, D-01187 Dresden, Germany — 3B.I. Verkin Institute for Low Temperature Physics and Engineering, Kharkov, 61103, Ukraine — 4University of Warwick, Department of Physics, Coventry CV4 7AL UK
We have investigated elastic properties of the spin-ice materials Dy2Ti2O7 (DTO) and Ho2Ti2O7 (HTO) for a wide range of temperature and magnetic field. Our studies of the sound characteristics for several acoustic modes evidence a renormalization of the sound velocity and the sound attenuation due to phase transformations at applied magnetic field as well as an interaction with low-energy magnetic excitations (topological defects). The most prominent anomalies are quasi-periodic peaks in the sound velocity and in the sound attenuation observed in DTO due to non-equilibrium processes arising in the external magnetic field. These results were analyzed theoretically using exchange-striction coupling, which shows a good agreement between theory and experiment. The obtained results at high magnetic fields exhibit some pronounced anomalies around 50 T for both compounds. Our calculations including crystal-electric field effects show satisfactory agreement with experiment.