Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 53: Magnetic Heuslers, half-metals and oxides

MA 53.8: Vortrag

Freitag, 5. April 2019, 11:30–11:45, H33

Microscopic understanding of the magnetic phase diagram of Gd_1−xCa_xMnO₃ — •Hichem Ben Hamed¹, Martin Hoffmann², Waheed A. Adeagbo¹, Arthur Ernst^2,3, Wolfram Hergert¹, Teemu Hynninen⁴, Kalevi Kokko⁴, and Petriina Paturi⁴ — ¹Institute of Physics, Martin Luther University Halle-Wittenberg, Germany — ²Institute for Theoretical Physics, Johannes Kepler University Linz, Austria — ³Max Planck Institute of Microstructure Physics, Halle, Germany — ⁴Department of Physics and Astronomy, University of Turku, Finland

Rare-earth doped manganites (RMnO₃) exhibit a rich variety of promising properties like colossal magnetoresistance, metal-insulator transition and multiferroicity for small rare-earth cations. These properties are primary controlled by the coupling between various types of structural, magnetic, charge and orbital degrees of freedom. The magnetic phase diagram of one prominent member of the RMnO₃ series, GdMnO₃ with Calcium (Ca) doping, is investigated by methods based on density functional theory and Monte Carlo simulations. A quasi-random distribution of Gd and Ca ions is adopted for each doping concentration.

A robust ferromagnetic (FM) ground state was obtained for the hole doped region (x < 0.5). On the other hand, a strong competition between FM and many different anti-ferromagnetic orders was found in the ( x > 0.5) region. These competitions are discussed in terms of the Heisenberg exchange interactions. Theoretical results are compared with experimental findings.