DFRT-PFM is an advanced piezoresponse imaging technique developed by Park Systems to overcome the limitations of conventional PFM. By using two frequencies for resonance tracking and another for actual piezoresponse detection, DFRT-PFM maintains stable, high-sensitivity measurements even as the resonance conditions change. This enables precise visualization and analysis of complex domain structures, polarization switching, and local electromechanical responses in a wide range of functional materials.

For a technical comparison between DFRT PFM and conventional PFM techniques, like Off resonance-PFM (OR-PFM) and Contact resonance-PFM (CR-PFM), measurements were carried out on the same region of the CuInP₂S₆ (CIPS) sample using consistent experimental parameters. The collected datasets consist of surface topography (height channel) along with vertical PFM amplitude and phase images from each method. DFRT PFM provides high-resolution feature delineation with minimal lateral noise. Conversely, conventional techniques display lateral noise artifacts, and OR-PFM notably fails to resolve many features. In the boxed regions of the images, a diagonal boundary—present in both topography and CR-PFM—is nearly indistinguishable in OR-PFM data. Such artifacts complicate accurate differentiation of true piezoresponse signals from topographic crosstalk, especially when the domain structure is unknown, potentially compromising data interpretation.