Measurement of BaTiO3 domain structure using ultrahigh vacuum - atomic force microscopy(UHV-AFM)

We report the nanoscopic properties of the clean, free surface of a BaTiO3 single crystal in an ultra-high vacuum. Atomic force microscopy, piezoelectric force microscopy and Kelvin force microscopy measurements show that the potential difference between upward and downward 180˚ domain is approx 100 mV. This value is 100 times smaller than the value estimated by using the standard 180˚ domain theory. Furthermore, our experiments show that this result cannot be explained only by the conventional explanations (that is, a decrease in the depolarization field by closure domains, the compensation of polarization bound charge by contamination or by oxygen excess and deficiency or ion transport). The results suggest a possibility that an intrinsic electrostatic shielding mechanism exists in the ferroelectrics and is essential for 180˚ domains. KCI Citation Count: 7