Asymmetric nanoscale switching in ferroelectric thin films by scanning force microscopy

Authors

Alexei Gruverman, University of Nebraska-LincolnFollow
A. Kholkin, University of AveiroFollow
A. I. Kingon, North Carolina State University, RaleighFollow
H. Tokumoto, Joint Research Center for Atom Technology—National Institute for Advanced Interdisciplinary Research (JRCAT-NAIR), Tsukuba, Ibaraki 305, Japan

Date of this Version

4-30-2001

Comments

Published in Appl. Phys. Lett., Vol. 78, No. 18, 30 April 2001. Copyright © 2001 American Institute of Physics. Used by permission.

Abstract

Scanning force microscopy (SFM) has been used to perform nanoscale studies of the switching behavior of Pb(Zr, Ti)O₃ thin films via the direct observation of their domain structures. The study revealed a significant asymmetry of a switching pattern which is a function of the voltage polarity and original domain structure of individual grains. The phenomenon of asymmetric switching is attributed (1) to the presence of an internal built-in electric field at the bottom interface and (2) to the mechanical stress exerted by the SFM tip. The former effect results in incomplete 180° switching, while the latter effect leads to a 90° rotation of the polarization vector. The resulting shear stress deformation of the grain underneath the tip combined with the applied field effect propels polarization reversal in the adjacent grains.