Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 3: Magnetic Half Metals and Oxides

MA 3.8: Vortrag

Montag, 23. März 2009, 12:45–13:00, HSZ 401

Effect of strain and magnetic interaction parameters in Fe₂O₃-FeTiO₃ heterostructures — •Hasan Sadat Nabi and Rossitza Pentcheva — Department of Earth and Environmental Sciences, University of Munich, Theresienstr. 41, 80333 Munich, Germany

The interfaces between complex oxides provide a challenging area to explore new functionality for the development of future devices. To explain the origin of interface magnetism in the Fe₂O₃ (canted antiferromanet)- FeTiO₃ (room temperature paramagnet) system we have performed density functional theory (DFT) calculation including a Hubbard U parameter. We find that the polar discontinuity at the interface is accommodated through a disproportionation in the Fe contact layer into Fe²⁺, Fe³⁺[1] giving the first theoretical evidence for the lamellar magnetism hypothesis [2].

Furthermore, by using the lateral lattice constant of different substrates (e.g. Fe₂O₃, FeTiO₃, Al₂O₃) we show how the electronic properties and energetic stability of the system can be tuned by strain. In addition, the magnetic exchange interaction parameters are extracted by mapping the DFT total energies of different spin-configurations on a Heisenberg Hamiltonian.

Funding by the German Science Foundation (DFG PE883/4-1), ESF (EuroMinSci-MICROMAGN) and a grant for computational time at the Leibniz Rechenzentrum are gratefully acknowledged.

[1] R. Pentcheva, H. Sadat Nabi, Phys. Rev. B, 77, 172405 (2008).

[2] Robinson, P. et al. Nature 418, 517 (2002).