Determination of Imprint Effects in Ferroelectrics from the Quantified Phase and Amplitude Response.

Piezoresponse force microscopy (PFM) is a robust characterization technique to explore ferroelectric properties at the nanoscale. However, the PFM signal can lead to misinterpretation of results due to the dominant electrostatic interaction between the tip and the sample. In this work, a detailed calibration process is presented and a procedure to identify the parasitic phase offset is demonstrated. To obtain artifact-free phase-amplitude loops, a methodology is developed by combining the outcomes from switching spectroscopy-PFM (SS-PFM) and Kelvin probe force microscopy (KPFM). It is demonstrated that the phase and amplitude loops obtained from SS-PFM at a specific read voltage, ascertained from the surface potential by KPFM, can convey accurate electromechanical information. These methodologies are applied to quantify the imprint voltage in BaTiO ₃ and BiFeO ₃ , along with vertically aligned BaTiO ₃ :Sm ₂ O ₃ and BaTiO ₃ :MgO nanocomposites. The variation of the imprint voltage measured under different tip voltages demonstrates the importance of selecting the correct read voltage in determining the local imprint voltage. Additionally, 2D imprint voltage maps in each domain of a BaTiO ₃ single crystal are obtained using the datacube-PFM technique, which allows pixel-by-pixel determination of artifact-free spatial variation of PFM phase-amplitude response.
Competing Interests: The authors declare no competing financial interest.
(© 2024 The Authors. Published by American Chemical Society.)