Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 3: Correlated Electrons: Frustrated Magnets - Pyrochlore Systems and Iridates

TT 3.10: Vortrag

Montag, 7. März 2016, 12:00–12:15, H20

On the search for magnetic correlations in double perovskites — •Franziska Hammerath^1,2, Rajib Sarkar¹, Sirko Kamusella¹, C. Baines³, H.-H. Klauss¹, T. Dey², Gizem Aslan Cansever², Kaustuv Manna², Andreas Zimmermann², Andrey Maljuk², Mihai Sturza², Dmitriy Efremov², Sabine Wurmehl², and Bernd Büchner² — ¹Institute for Solid State Physics, Dresden Technical University, TU Dresden, 01062 Dresden, Germany — ²IFW Dresden, Institute for Solid State Research, PF 270116, 01171 Dresden, Germany — ³Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen, PSI, Switzerland

The cubic double perovskite Ba₂YIrO₆ has been investigated by the local probe techniques NMR and µSR. Both methods confirm the absence of long range order in this compound, but observe signatures of magnetic correlations: The NMR spin-lattice relaxation rate suggests the presence of growing magnetic correlations at low temperatures. An increase of the µSR spin-lattice relaxation rate confirms the presence of weak magnetism. These findings cannot be explained by the recently suggested excitonic type of magnetism [1], but also go beyond a simple nonmagnetic ground state picture of the 5d⁴ (J_eff=0) electronic configuration of Ir⁵⁺. In the monoclinic analog Sr₂YIrO₆, the NMR line width and spin-lattice relaxation rates reveal a nonmagnetic behavior, in contrast to a first report [2], but in line with a recent study [3].
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