Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 23: Magnetic Heuslers, Half-Metals, Semiconductors, and Oxides (organized by MA)

TT 23.6: Talk

Monday, March 16, 2015, 16:15–16:30, H 1012

Ab initio study of the magnetic properties of Sr₂FeMoO₆ with defects — •Martin Hoffmann^1,2, Victor N. Antonov³, Wolfram Hergert¹, Arthur Ernst^2,4, and Lev Bekenov³ — ¹Martin Luther University Halle Wittenberg, Germany — ²Max Planck Institute of Microstructure Physics, Halle, Germany — ³Institute for Metal Physics, Kiev, Ukraine — ⁴University Leipzig, Germany

We used first-principle calculations with the Korringa-Kohn-Rostoker Green function method to systematically investigate the electronic and magnetic properties of Sr₂FeMoO₆ (SFMO). We applied self-interaction correction and GGA+U to take into account the correlation effects and obtain the half-metallic nature of the material. The Curie temperature T_C was obtained from calculated magnetic exchange interactions which were used in a Monte Carlo simulation.

For a continuously increasing U parameter, SFMO became half-metallic but the T_C decreased below the reported values for bulk SFMO. We investigated possibilities to find a better agreement with experiment. This might be shortcomings in the description of the electronic structure, changes in the valency of Fe or the appearance of defects like antisite disorder and oxygen vacancies.

In addition, x-ray absorption spectra were simulated with the linear muffin-tin orbital method and compared to experimental results. A good agreement was only obtained by considering a contribution of Fe²⁺ and oxygen vacancies.