Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 18: Correlated Electrons: Spin Systems and Itinerant Magnets – Frustrated Magnets 2 (jointly with MA)
TT 18.8: Talk
Monday, March 16, 2015, 17:00–17:15, H 3005
Comparison between dynamical permeability and permittivity in Dy2Ti2O7 at low temperatures — •Steffen Harms1, Christoph P. Grams1, Martin Valldor2, and Joachim Hemberger1 — 1II. Physikalisches Institut, Universität zu Köln, Cologne, Germany — 2Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
Dy2Ti2O7 if one of the well known spin-ice compounds in which magnetic monopoles are emergent [1]. It was predicted, that these monopoles carry electric dipole moments [2] and therefore the monopole dynamics can be seen in the dielectrical response ε*(ν).
Recently published data exhibits the speeding up of a dielectric relaxation process reaching a relaxation rate of up to ν0=100 kHz near the critical-endpoint of the (H,T)-phase diagram [3]. This process can be associated with the hopping of magnetic monopoles and should among other contributions also be seen in the magnetic ac-susceptibility.
Here we present a comparative broadband study of complex permittivity and permeability in the mK range in order to disentangle the different contributions to the dynamic response in the spin-ice Dy2Ti2O7.
Funded through the Institutional Strategy of the University of Cologne within the German Excellence Initiative and research grant HE-3219/2-1.
[1] C. Castelnovo et al., Nature 451, 42 (2008).
[2] D. I. Khomskii, Nature Communications 3, 1 (2012).
[3] C. P. Grams et al., Nature Communications 5, 4853 (2014).