Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 35: Magnetic Oxides and Shape Memory Alloys (jointly with MM)

MA 35.5: Vortrag

Donnerstag, 14. März 2013, 10:30–10:45, H23

Impact of oxygen vacancies on the magnetic properties of SrCoO_3−δ — •Martin Hoffmann^1,2, Vladislav S. Borisov², Igor V. Maznichenko¹, Sergey Ostanin¹, Ingrid Mertig¹, Wolfram Hergert¹, and Arthur Ernst² — ¹Institute of Physics, Martin Luther University Halle Wittenberg, Germany — ²Max Planck Institute of Microstructure Physics, Halle, Germany

Experimental studies have shown that the perovskite SrCoO_3−δ with δ≤ 0.06 is a ferromagnetic metal. Due to a small lattice mismatch, this material could be used as an electrode in functional multicomponent systems with ABO₃ structure. Magnetic properties such as the critical temperature and the magnetic moment obtained in several measurements vary between 210-305K and 1.5-3µ_B, respectively. Former theoretical investigations of this material still lack a proper description of the magnetic properties of SrCoO_3−δ. Furthermore, oxygen vacancies are not considered previously. We explain the experimental results from the ab-initio point of view using a Korringa-Kohn-Rostoker (KKR) Green function method.

By means of the coherent-potential approximation, we model different amounts of randomly distributed oxygen vacancies and investigate the behavior of the Curie temperature T_C. Although the absolute values for T_C are too large, the gradient agrees well with experiments. To improve the absolute values, we considered the strongly correlated character of the d-orbitals of Co by applying the LDA+U method.