STRESS-INDUCED DEPOLARIZATION IN PZT THIN-FILMS, MEASURED BY MEANS OFELECTRIC FORCE MICROSCOPY

During the procedure of poling selected crystallites on thin ferroelec tric lead zirconate titanate films (PZT) by means of an electric scann ing force microscope (EFM), strong depolarization vertical to the him has been found. This can be shown to be due to stress induced effects, and the stress can be quantified. The stress originates from Maxwell stress between the EFM-tip and the dielectric sample. It has been foun d that the depolarization is set off at 93 MPa and continues until 260 MPa. The ferroelectric behaviour of the films is not damaged, and the poling behaviour remains reproducible. As explained, the field- and s tress-induced poling characteristics can be ascribed to domain reorien tation processes. Therefore, EFM can characterize domain configuration s by means of stress dependent polarization measurements. This is true even if the domains cannot be resolved because of their small dimensi ons. The use of stress dependent polarization measurements significant ly extends the efficiency of EF microscopy. (C) 1998 Elsevier Science B.V. All rights reserved.