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TT: Fachverband Tiefe Temperaturen

TT 6: Surface magnetism and magnetic coupling phenomena (joint session MA/O/TT)

TT 6.12: 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 SrMn_0.5Ir_0.5O₃ 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.