Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Frustrated Magnets - Pyrochlore Systems and Iridates
TT 3.11: Vortrag
Montag, 7. März 2016, 12:15–12:30, H20
High-field multi-frequency ESR spectroscopy of La2CuIrO6 — •Stephan Fuchs1, Vladislav Kataev1, Kaustuv Manna1, Sabine Wurmehl1, Anup Kumar Bera3, Andrey Malyuk1, and Bernd Büchner1,2 — 1Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden,D-01171 — 2Institut für Festkörperphysik, Technische Universität Dresden,D-01062 — 3Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
We will present the electron spin resonance results of the double perovskite La2CuIrO6. This material provides a playground to examine the magnetic interactions in a 5d transition metal oxide with strong spin-orbit coupling. Measurements of the static magnetization M(T,H) show an antiferromagnetic ordering at TAFM = 74 K and a weak ferromagnetic moment below 54 K. ESR measurements of the powder sample were carried out for several temperatures and frequencies to determine the g-factor and the magnetic exaction gap. Our goal is to identify the origin of the ferromagnetic contribution with ESR. We observe an opening of the ferromagnetic gap at T=93 K (> TAFM) which continuously develops over the TAFM down to low temperature. The complex interaction of the Cu- and Ir-spin gives rise to the continuous shift of the g-factor: By decreasing the temperature, the Ir spins are getting progressively more involved in the resonance of the statically ordered Cu spin lattice due to exchange coupling between the two sublattices. We conclude that the weak ferromagnetic component in La2CuIrO6 is intrinsic which points at a noncollinear spin-structure in the ordered state.