Berlin 2008 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 5: Scanning and diffraction methods

DF 5.4: Vortrag

Montag, 25. Februar 2008, 15:50–16:10, EB 407

Electromechanical force microscopy as a non-destructive detection of local inhomgeneities with nanoscale — •Serge Röhrig and Andreas Rüdiger — Institute of Solid Research, Research Center Jülich, Germany

Detection of crystallographic defects and inhomgeneities is typically achieved by either non-destructive light or sound scattering with a lateral resolution of the order of the used wavelength or in a destructive way with atomic resolution by means of e.g. TEM. We present a non-destructive approach based on a standard piezoresponse force microscope detecting the second harmonic of the excitation voltage i.e. the electrostrictive response with nanometer resolution. We use the lateral torsion of the cantilever to monitor displacements that stem from any reduction of radial symmetry underneath the tip. While a globally reduced radial symmetry e.g. due to orthorhombic symmetry of the sample generates an undetectable background, any local variation causes a torque on the cantilever that can be monitored without need for any piezoelectric activity. We demonstrate the feasibility of this technique that is generally applicable to all crystalline dielectrics on any lengthscale.