Regensburg 2019 – wissenschaftliches Programm
MA 5.12: Vortrag
Montag, 1. April 2019, 12:30–12:45, H53
Charge-transfer driven ferromagnetism in a disordered three-dimensional 3d-5d spin system — •Philipp Komissinskiy1, Supratik Dasgupta1, Ilya Radulov1, Andrei Rogalev2, Fabrice Wilhelm2, Marton Major1, and Lambert Alff1 — 1Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany — 2European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
A three-dimensional disordered spin system consisting of the 3d transitional metal ion Mn4+ with strong electronic correlations and the heavy 5d transition metal ion Ir4+ with large spin-orbit coupling has been investigated in form of a perovskite thin film. The studied compound of the composition SrMn0.5Ir0.5O3 does not exist as bulk or single crystal, but can be stabilized by epitaxy as fully disordered double perovskite thin film onto SrTiO3 single-crystal substrate using pulsed laser deposition. As measured by X-ray circular dichroism, the ground state of this material is ferromagnetic with both, Mn and Ir, spins aligned in parallel. This unusual ground state can be qualitatively explained by charge-transfer driven magnetic exchange involving the effective J=1/2 state of Ir. Due to the coexistence of competing magnetic interactions and randomness in the system, spin-glass features are observed at low temperatures.