This application note presents a primer on the direct and reverse piezoelectric effects and their uses, and the instrumentation and applications of piezoresponse force microscopy.
The document provides a primer on piezoelectricity, covering the historical discovery by the Curie brothers and defining both the direct effect (mechanical stress creating electric charge) and the reverse effect (electric field producing mechanical strain). It discusses various applications of these effects in sensors, actuators, ultrasonics, and microtechnology.
A significant portion is dedicated to Piezoresponse Force Microscopy (PFM), a scanning probe microscopy technique based on the reverse piezoelectric effect. The text describes PFM as an imaging mode derived from Contact Mode AFM, where an electric field applied to a sample causes expansion or contraction measured by the deflection of an AFM cantilever. It outlines the experimental setup involving lock-in amplifiers and explains how PFM is used to characterize piezoelectric properties at the nanometer scale.
PFM is a scanning probe microscopy technique that probes a sample's mechanical response to an applied electric field.
The frequency is typically far from below the fundamental resonance frequency to avoid driving the cantilever into resonant oscillations.