Regensburg 2010 – wissenschaftliches Programm

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KR: Fachverband Kristallographie

KR 10: Poster: Multiferroics (with MA, DF, KR, DS)

KR 10.14: Poster

Dienstag, 23. März 2010, 10:45–13:45, Poster A

Magnetism and ferroelectricity of Mn-doped BaTiO₃ thin films — •Yao Shuai, Danilo Bürger, Shengqiang Zhou, Manfred Helm, and Heidemarie Schmidt — Forschungszentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400, 01328 Dresden

Strained BaTiO₃ (BTO) thin films grown by pulsed-laser deposition (PLD) on SrTiO₃ substrates can result in a nearly 500 K larger ferroelectric transition temperature. The remanent polarization of strained BTO thin films is at least 250% higher than that in BTO single crystals [1]. We used PLD to grow Mn-doped BTO (BTMO) thin films on MgO, and c-plane sapphire substrates. For example, we observed XRD reflexes of (00l)- and (l00)-oriented domains on BTMO deposited on MgO and sapphire, indicating the BTMO films are polycrystalline. At room temperature the saturated magnetic moment of BTMO films with a thickness of 400nm on MgO substrates amounted to 8 emu/cm³, while that of the films deposited on c-sapphire was merely 1 emu/cm³ even at 5 K, resulting from a weak domain orientation due to the large lattice mismatch between BTMO and c-sapphire. A capacitance-voltage hysteresis behavior of BTMO films on Pt/c-sapphire has been probed under a driving voltage of 50 mV at 100 kHz, which can be ascribed to the nonlinear ferroelectric response [2]. The simultaneously observed magnetic and ferroelectric ordering proves the feasibility of multiferroic BTMO for novel device applications[3]. [1] K. J. Choi et al., Science 306 (2004) 1005. [2] M. Dawber et al., Reviews of Modern Physics 77 (2005) 1083. [3] R. Ramesh et al., Nature Materials 6 (2007) 21. (2007) 21.