Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 38: Multiferroics

MA 38.7: Talk

Thursday, March 26, 2009, 16:45–17:00, HSZ 103

Magnetic phase transition at a biferroic interface predicted from first principles — •Michael Fechner¹, Igor Maznichenko², Sergey Ostanin¹, Arthur Ernst¹, Jürgen Henk¹, Patrick Bruno³, and Ingrid Mertig^1,2 — ¹MPI für Mikrostrukturphysik Halle, Germany — ²Martin-Luther-Universität Halle-Wittenberg, Germany — ³European Synchrotron Radiation Facility Grenoble, France

On the basis of first-principles electronic-structure calculations we predict that epitaxial multiferroic films—fabricated as ultrathin Fe films deposited on TiO₂-terminated (001) surfaces of ATiO₃ perovskites (A = Pb, Ba)—exhibit an unexpected change of their magnetic structure with increasing Fe-film thickness. The magnetic order changes from ferromagnetic, with a magnetization of about 3µ_B/atom for the 1-monolayer system, to ferrimagnetic with almost vanishing magnetization upon deposition of a second Fe layer. Ferromagnetic order is restored for thicker Fe films but with significantly reduced magnetization as compared to Fe bulk. The effect is understood in terms of hybridization of electronic states and geometric structure. The magnetoelectric coupling affects the size of the magnetic moments moderately, a spin-reorientation transition is not found.