Ferroelectric Patterning with High Fields: Ferroelectric oxides have a net polarization that can switch direction upon application of a sufficiently high electric field. In principle, a ferroelectric thin film should be able to act as a polar switch—tunneling an electron through the film would effectively switch on or off depending on the direction of the polarization. In practice, the length scale needed for a sufficiently small tunneling barrier is nearly the same as the scale at which films no longer support ferroelectricity. Maksymovych et al. (p. 1421 ) now show that the tip of an atomic force microscope can be used to pattern polarization domains in a thin film of lead zirconate titanate in high electric fields similar to those for field emission tips.

The application of ferroelectric materials for electronic devices necessitates the quantitative study of local switching behavior, including imprint, coercive bias, remanent and saturation responses, and work of switching. Here we introduce switching spectroscopy piezoresponse force microscopy as a tool for real-space imaging of switching properties on the nanoscale. The hysteresis curves, acquired at each point in the image, are analyzed in the thermodynamic and kinetic limits. We expect that this approach will further understanding of the relationships between material microstructure and polarization switching phenomena on the nanoscale, and provide a quantitative tool for ferroelectric-based device characterization.

Mapping energy transformation pathways and dissipation on the nanoscale and understanding the role of local structure on dissipative behavior is a challenge for imaging in areas ranging from electronics and information technologies to efficient energy production. Here we develop a novel Scanning Probe Microscopy (SPM) technique in which the cantilever is excited and the response is recorded over a band of frequencies simultaneously rather than at a single frequency as in conventional SPMs. This band excitation (BE) SPM allows very rapid acquisition of the full frequency response at each point (i.e. transfer function) in an image and in particular enables the direct measurement of energy dissipation through the determination of the Q-factor of the cantilever-sample system. The BE method is demonstrated for force-distance and voltage spectroscopies and for magnetic dissipation imaging with sensitivity close to the thermomechanical limit. The applicability of BE for various SPMs is analyzed, and the method is expected to be universally applicable to all ambient and liquid SPMs.

The transport physics of domain wall conductivity in La-doped bismuth ferrite (BiFeO3) has been probed using variable temperature conducting atomic force microscopy and piezoresponse force microscopy in samples with arrays of domain walls in the as-grown state. Nanoscale current measurements are investigated as a function of bias and temperature and are shown to be consistent with distinct electronic properties at the domain walls leading to changes in the observed local conductivity. Our observation is well described within a band picture of the observed electronic conduction. Finally, we demonstrate an additional degree of control of the wall conductivity through chemical doping with oxygen vacancies, thus influencing the local conductive state.