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DF: Dielektrische Festkörper

DF 4: Poster

DF 4.11: Poster

Samstag, 5. März 2005, 08:30–16:30, Poster TU C

Structural and electrical characterization of multiferroic BiFeO₃ thin films — •Claus-Henning Solterbeck, Mohamed Bouazza, Serguei Iakovlev, and Mohammed Es-Souni — Institute for Materials and Surface Technology, University of Applied Sciences, Kiel

Pure and Gd-doped polycrystalline BiFeO₃ thin films were fabricated by chemical solution deposition. The microstructural characterization was performed by X-ray diffractometry, electron microscopy, and atomic force microscopy. The films show a preferred out-of-plane orientation of (100) (pseudocubic). Annealing in oxygen instead of air leads to smaller roughness and grain size.

Emphasis was put on the electrical properties, which were characterized by measurements of the polarization, leakage current, and impedance as well as the piezoeletric coefficient. The films have a relatively weak ferroelectric polarization, 2  P_r, of approximately 1 µ C/cm² and a low frequency dispersion of the dielectric constant. The resistance depends drastically on the atmosphere during crystallization with an increase by two orders of magnitude when annealing in oxygen. The piezoeletric coefficient d₃₃ of samples annealed in oxygen has a value of 12  pm/V.

Preliminary magnetic measurements are reported, too. BiFeO₃ has a small magnetic hysteresis with a coercitivity of 230  G.