[29] Surface charge dynamics on ferroelectric PbZr_0.48Ti_0.52O₃ films responding to the switching bias of electric force microscope

We investigated the role of surface charges in writing and reading ferroelectric bits on an epitaxial PbZr_0.48Ti_0.52O₃ thin film by electric force microscopy (EFM). The sign of EFM surface potential was reversed within several hundred microseconds for 10 V. For a negative bias voltage of −10 V, EFM surface potential was reversed in several milliseconds. The different time scales of the EFM surface potential reversals originate from the screening of the ferroelectric polarization charges by the surface charges which pass over two different Schottky barriers depending on the applied bias polarity.