Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 30: Correlated Electrons: Spin Systems and Itinerant Magnets – Frustrated Magnets 3 (jointly with MA)

TT 30.6: Talk

Tuesday, March 17, 2015, 10:45–11:00, H 0110

Magnetic properties in hexagonal iridates — •Friedrich Freund, Soham Manni, and Philipp Gegenwart — EP VI, Center for Electronic Correlations and Magnetism, Augsburg University, 86159 Augsburg, Germany

Hexagonal iridates A₂IrO₃ (A=Na or Li) are promising candidates for the realization of the Kitaev interaction, which is an anisotropic and bonding dependent interaction that can lead to novel types of spin liquid behavior. We report the synthesis, characterization and magnetic properties of poly- and single crystals of Na₂IrO₃ and two polytypes of Li₂IrO₃ [1,2]. All three materials have a threefold coordination of edge sharing IrO₆ octahedra giving rise to Kitaev exchange. While Na₂IrO₃ and α-Li₂IrO₃ form planar honeycomb layers a three-dimensional network is realized in β-Li₂IrO₃. At high temperatures, the magnetic susceptibility of all systems displays Curie-Weiss behavior with fluctuating effective 1/2 moments while at low temperatures differently ordered states are found whose properties have been investigated by neutron powder diffraction, resonant x-ray diffraction and inelastic neutron scattering [3,4].

Work in collaboration with A. Biffin, R. D. Johnson, Sungkyun Choi, A. Bombardi, P. Manuel, R. Coldea, A. Jesche and Y. Singh.

[1] Y. Singh et al., PRL 108, 127203 (2012).

[2] T. Takayama et al., arXiv:1403.3296 (2014).

[3] A. Biffin et al., PRB 90, 205116 (2014).

[4] S.K. Choi et al., PRL 108, 127204 (2012).