Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 71: Correlated Electrons: Poster Session
TT 71.43: Poster
Mittwoch, 18. März 2015, 15:00–18:00, Poster B
Dielectric measurements of magnetic monopoles on the spin-ice compounds (Ho/Dy)2Ti2O7 — •Manuel Pietsch, Christoph P. Grams, Jean-Francois Welter, Victoria Cho, Thomas Lorenz, and Joachim Hemberger — II. Physikalisches Institut, Universität zu Köln, Cologne, Germany
In so-called spin-ice compounds a frustrated ground-state with finite zero-point entropy is stabilized via competing interactions and emergent magnetic monopoles excitations [1]. It was postulated that a magnetic monopole holds an electric dipole moment [2], which allows to investigate their dynamics via the dielectric function ε(ν).
In Dy2Ti2O7 a critical speeding-up for frequencies up to 100 kHz was reported down to temperatures of 200 mK with a specific focus on the critical endpoint present for a [111] magnetic field [3]. In Ho2Ti2O7 both faster relaxation dynamics compared to the sister-compound and an additional relaxation process are suspected [4].
Here we report on broadband dielectric spectroscopy measurements of ε(ν) in Ho2Ti2O7.
Funded through the Institutional Strategy of the University of Cologne within the QM2 Excellence Initative and research grant HE-3219/2-1.
[1] C. Castelnovo et al., Nature 451 (2008) 42
[2] D. I. Khomskii, Nature Comm. 3 (2012) 1
[3] C.P. Grams et al., Nature Comm. 5 (2014) 4853
[4] G. Ehlers et al., J. Phys.: Cond. Mat. 16 (2004) S635