Berlin 2008 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 5: Scanning and diffraction methods

DF 5.3: Vortrag

Montag, 25. Februar 2008, 15:30–15:50, EB 407

Complete reconstruction of the piezoelectric tensor in BaTiO₃ nanoislands — •Sebastian Albiez, Serge Röhrig, and Andreas Rüdiger — Institut für Festkörperfosrschung, Forschungszentrum Jülich, 52425 Jülich

Due to the advancing miniaturization of non-volatile ferroelectric memories, a better separation of extrinsic and intrinsic contributions becomes mandatory. Piezoresponse force microscopy (PFM) is the favored tool to investigate these phenomena as the third rank-piezoelectric tensor represents the crystallographic structure of the system and thus also allows for the discussion of the polarization. Current PFM systems achieve lateral resolutions of a few nanometers. The piezoelectric tensor describes the three-dimensional displacement of the tip in contact with the surface i.e. three linearly independent orthogonal forces on the tip. The optical lever arm method however only detects a lateral and a vertical displacement the latter one containing the information of vertical bending and vertical buckling while the first one only contains the information of lateral torsion. To disentangle these contributions a 90-degree rotation of the sample underneath the tip is required without losing the area under investigation. We present current experimental data on ferroelectric nanoislands and discuss them in terms of a complete reconstruction of the piezoelectric tensor where all three displacement modes of the cantilever are differentiated.