Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 44: PhD Symposium Quantum Magnets (contributed talks)

MA 44.9: Vortrag

Mittwoch, 22. März 2017, 17:15–17:30, HSZ 403

Comparison between dynamical permeability and permittivity in Dy₂Ti₂O₇ at low temperatures — •Steffen Harms¹, Christoph P. Grams¹, Martin Valldor², Johanna Frielingsdorf¹, Thomas Lorenz¹, and Joachim Hemberger¹ — ¹Institute of Physics II, University of Cologne, Germany — ²Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

Dy₂Ti₂O₇ is one of the well known spin-ice compounds in which magnetic monopoles are emergent [1]. These monopoles carry electric dipoles [2] and therefore their dynamics is apparent in the dielectrical response ε^*(ν). Recently published data reveal the speeding up of a dielectric relaxation process reaching a relaxation rate of up to ν ∼ 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, leave a fingerprint in the magnetic ac-permeability. 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.

[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).