Scanning probe microscopy was used to form local polarized domains in ferroelectric thin films by applying a voltage between the gold-coated cantilever and the conductive substrate in contact mode. Two methods of visualizing the poled areas are described. The first is to detect the piezoelectric response of the films by applying a small oscillating voltage between the probe tip and the substrate. This measurement determines the local ferroelectric polarity and domain structure directly. The second method is to measure the surface potential of the poled films using scanning Maxwell stress microscopy. This does not directly address the ferroelectric behavior of the film, but rather the potential due to surface charge. We determined the surface potential dependence on pulse voltage and duration applied to the ferroelectric film. The results demonstrate that the charged area will increase rapidly, but the surface potential will saturate as the pulse voltage and duration are increased. The resultant stable localized surface charge features indicate that lead zirconate titanate thin films are promising candidates for high-density charge storage media.

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Lead zirconate titanate (PZT) thin film was formed on Pt/Ta/Si3N4/Si(100) substrate at 400 °C by sputtering and then annealed at 650 °C in air. The PZT film was 1 μm thick and had dielectric permittivity of 980, loss tangent of 0.05, remanent polarization of 31 μC/cm2, and coercive field of 110 kV/cm. Piezoelectric property of the film formed on silicon cantilever was estimated from the converse effect. Poling at 5 kV/mm increased the property by a factor of 1.2 to 3.4, resulting in converse piezoelectric constant (d31) varying from −84 to −102 pC/N.

Friction force microscopy ͑FFM͒ was used to distinguish the different surface terminations on the nanoscale on atomically flat SrTiO 3 ͑001͒ surfaces, obtained by a combination of ultrasonic agitation and subsequent annealing in air at 1000°C. The surface exhibits atomically flat terraces and sharp steps whose height is 0.2 nm, corresponding to half the height of a unit cell of SrTiO 3 , or a single atomic layer, where strong friction contrast appears. A compositional analysis of the topmost surface by coaxial-impact-collision ion-scattering spectroscopy ͑CAICISS͒ indicated that the friction contrast corresponded to different surface terminations, namely, the SrO and TiO 2 layer as a topmost surface, where the TiO 2 domain was dominant. This is further supported by the correlation between the compositional Sr/Ti ratio and the area ratio which was observed by CAICISS and FFM, respectively.

A friction force microscope study in ultrahigh vacuum was conducted on an atomically flat SrTiO3(001) surface, where SrO and TiO2 domains were distinguished by the difference in friction force. It is revealed that the friction on the SrO became stronger with water adsorption relative to the TiO2 layer. The selective change in friction is attributed to the chemical reaction occurring on the SrO layer, which is supported by the results of x-ray photoelectron spectroscopy.