Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 3: Methods: Scanning probe techniques I

O 3.1: Vortrag

Montag, 22. März 2010, 11:15–11:30, H32

Contrast mechanisms for the detection of ferroelectric domains with scanning force microscopy — •Tobias Jungk, Florian Johann, Akos Hoffmann, and Elisabeth Soergel — Physikalisches Institut, Universität Bonn, Wegelerstrasse 8, 53115 Bonn

We present an analysis of the contrast mechanisms for the detection of ferroelectric domains on all faces of bulk single crystals using scanning force microscopy. The experiments were carried out with hexagonally poled lithium niobate to access well-defined domain structures on every crystal face [1]. Using a rotation stage including subsequent image processing allows for the discrimination of deflection and buckling from the vertical signal, which – together with the lateral signal – yield all accessible information [2]. Thus, the domain contrast can be attributed to three different mechanisms: (i) the thickness change of the sample due to an out-of plane piezoelectric response, (ii) the lateral displacement of the sample surface due to an in-plane piezoresponse and (iii) an expansion/contraction movement in the vicinity of the domain wall on the crystallographic y- and z-faces. A careful analysis of the movement of the cantilever with respect to its orientation relative to the crystallographic axes of the sample allows a clear attribution of the observed domain contrast to the corresponding driving forces.

[1] T. Jungk, A. Hoffmann, and E. Soergel, New J. Phys. 11, 033029 (2009).

[2] F. Johann, T. Jungk, S. Lisinski, A. Hoffmann, L. Ratke, and E. Soergel, Appl.  Phys. Lett.  95, 202901 (2009).