Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: Magnetic Thin Films II

MA 20.3: Vortrag

Mittwoch, 28. März 2007, 15:45–16:00, H5

Magnetism and magnetoelectric properties of multiferroic HoMnO₃ thin films — •Jong-Woo Kim¹, Kathrin Dörr¹, Konstantin Nenkov¹, Ludwig Schultz¹, Bas B. van Aken², and Manfred Fiebig² — ¹Institute for Metallic Materials, IFW Dresden, Postfach 270116, 01171 Dresden, Germany — ²HISKP, Universität Bonn, Nussallee 14-16, 53115 Bonn, Germany

Hexagonal HoMnO₃, one of the most promising single-phase multiferroics, has received much interest because of its strong magnetoelectric effect [1,2]. We have grown twin-free epitaxial HoMnO₃ films of thicknesses from 25 nm to 240 nm on (111) Y:ZrO₂ (YSZ) substrates by pulsed laser deposition. Ferroelectric polar order and Mn antiferromagnetism of the films has been observed by optical second harmonic generation [3]. Magnetization measurements reveal magnetic Ho ordering which is, with subtle deviations, similar to that of bulk crystals.

For the investigation of magnetoelectric properties, trilayer capacitor structures using an epitaxial Pt bottom electrode have been prepared. Measurements of the electric polarization at such trilayers demonstrate ferroelectric switching at 300 K, inspite a certain degree of leakage. Measurements of the magnetoelectric response in both ways, i. e. of the electric polarization vs. magnetic field and of the magnetization vs. electric field are in progress.

[1] F. Yen, et al., Phys. Rev. B 71, 180407 (2005)

[2] T. Lottermoser, et al., Nature 430, 541 (2004)

[3] J.-W. Kim et al., Appl. Phys. Lett. (in press)