Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 71: Correlated Electrons: Poster Session

TT 71.39: Poster

Mittwoch, 18. März 2015, 15:00–18:00, Poster B

Local magnetic properties of diluted honeycomb iridates Na_3−δMIr₂O₆ (M = Zn, Cu, Ni) probed by ²³Na-NMR and µ⁺SR — Giacomo Prando¹, Evgeniya Vavilova^1,2, Alexey Alfonsov¹, Hans-Joachim Grafe¹, •Vladislav Kataev¹, Bernd Büchner^1,3, Kristen Baroudi⁴, Cindi Yim⁴, John Roudebush⁴, Huiwen Ji⁴, and Robert Cava⁴ — ¹Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, D-01171 Dresden, Germany — ²Zavoisky Physical Technical Institute of RAS, Kazan, Russia — ³Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany — ⁴Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA

We present an experimental investigation of the magnetic properties of a series of sodium ternary iridates Na_3−δMIr₂O₆ (M = Zn, Cu, Ni) by means of local spin-probe techniques. In these materials, Ir ions are arranged in hexagonal honeycomb layers while the transition metal ions M substitute the Na ions in the hexagons center, with some detected degree of M/Ir site mixing [1]. Together with our earlier magnetization measurements [1], our results give evidence that the doping of the Ir honeycomb lattice has a remarkable impact on the overall magnetic properties. In contrast to a well-defined long-range antiferromagnetic (AF) order in Na₂IrO₃, our data clearly reveal two different regimes at low temperatures, namely a static AF ordering and a spin glass behavior with short range spin correlations. The interplay and coexistence of these regimes depends on the specific element M.

[1] K. Baroudi et al., Journ. Sol. State Chem. 210, 195 (2014)