Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 7: Correlated Electrons: Spin Systems, Itinerant Magnets 1
TT 7.13: Talk
Monday, March 11, 2013, 12:45–13:00, H19
Anisotropic magnetic Heat Transport in the Spin-Ice Compound Dy2Ti2O7 — •Simon Scharffe, Gerhard Kolland, Oliver Breunig, Martin Hiertz, Martin Valldor, and Thomas Lorenz — II. Physikalisches Institut, Universität zu Köln, Germany
The spin-ice compound Dy2Ti2O7 is a geometrically frustrated spin system which recently attracted attention due to emerging magnetic monopoles. It consists of corner-sharing Dy3+ tetrahedra which form a pyrochlore lattice. Due to strong crystal field effects an Ising anisotropy is present which aligns the Dy3+ spins along their local easy-axis in the {111}-directions, pointing into or out of the tetrahedra. The ground state below 1 K is given by the “ice-rule”: two spins point into and two out of a tetrahedron. Excited states can be created by flipping one spin, leading to neighboring “1-in/3-out” and “3-in/1-out” configurations. In zero magnetic field, these excitations can deconfine and are discussed as magnetic monopoles. Recently, κ has been studied for B→ || [001] and gives evidence for considerable monopole heat transport [1]. Here, we focus on the magnetic field anisotropy of κmag as for B→ || [110] and B→ || [111] exotic ground states of different degeneracies can be stabilized. In order to separate the phononic and magnetic contribution to κ, we also investigated (Dy0.5Y0.5)2Ti2O7 which is a magnetic reference system with suppressed spin-ice features.
This work was supported by the DFG through SFB 608.
[1] Kolland et. al. (2012), PRB, 86(060402)