Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 37: Magnetic Semiconductors II

MA 37.8: Vortrag

Mittwoch, 16. März 2011, 16:30–16:45, HSZ 401

Magnetism and correlation effects in "d⁰" magnetic oxides — •Ivetta Slipukhina, Phivos Mavropoulos, Stefan Blügel, and Marjana Ležaić — Peter Grünberg Institut & Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

In the past few years there is a growing interest in engineering a ferromagnetic state in otherwise nonmagnetic insulators by doping with sp elements instead of transition metals that is traditionally used in diluted magnetic semiconductors. This novel magnetic materials design was stimulated by several unexpected experimental observations of room-temperature ferromagnetism in highly defective wide-gap semiconductors and insulators and is particularly interesting, both from fundamental and practical point of view. In this presentation we discuss possible d⁰-magnetism in some otherwise non-magnetic oxides, using first-principles calculations within GGA and GGA+U approaches. Starting from Nitrogen doped MgO as a model system, we show that strong on-site electron interactions could lead to relative spin and orbital ordering of the Nitrogen induced hole states and significantly reduce the ferromagnetic exchange interaction. We discuss the mechanism behind the ferro- or antiferromagnetic state stabilization at different orbitally ordered configurations and analyze the influence of structural distortions on the magnetic interactions. The importance of structural distortions and strong electron correlations in Nitrogen doped SrTiO₃ perovskite is also examined. We gratefully acknowledge the support from HGF Nachwuchsgruppe Programme VH-NG-409.