Application of scanning capacitance force microscopy for detecting impurity phases in ferroelectric triglycine sulfate

An inhomogeneous ferroelectric (triglycine-sulfate (TGS) single crystal with a TGS–TGS+Cr periodic growth impurity structure) has been investigated by scanning capacitance force microscopy (SCFM). The specific features of mapping capacitance variations when detecting the electrostatic force at double and triple resonance frequencies are considered. The piezoelectric response, surface potential, and surface topography have been measured. It is shown that the capacitance contrast is formed both on domain walls and on TGS and TGS+Cr stripes. It is demonstrated that SCFM at the electrostatic-force double resonance frequency makes it possible to observe the spatial impurity distribution in the ferroelectric structure in the range of Cr concentrations of about 0.02–0.08 wt %.