In this article, we reported the studies on the local dual-peak vibrations in ferroelectric P(VDF-TrFE) films, induced by an alternating voltage with its amplitude high enough to cause polarization reversal. A further study showed that this dual-peak vibration was caused by ferroelectric switching process. The buildup of these dual-peak vibrations had been detected, and the asymmetrical evolution of local butterfly loops was observed. It was believed that the observed time delay during the developments of dual-peak vibrations and butterfly loops should be attributed to the electrode effect. (c) 2006 Wiley Periodicals, Inc.