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As a consequence of elasticity, mechanical deformations of crystals occur on a length scale comparable to their thickness. This is exemplified by applying a homogeneous electric field to a multidomain ferroelectric crystal: As one domain is expanding, the adjacent ones are contracting, leading to clamping at the domain boundaries. The piezomechanically driven surface corrugation of micron-sized domain patterns in thick crystals using large-area top electrodes is thus drastically suppressed, barely accessible by means of piezoresponse force microscopy. [ABSTRACT FROM AUTHOR]

A stochastic description is applied in order to understand how ferroelectric structures can be formed. The predictions are compared with experimental data of the so-called electrical fixing: domains are patterned in photorefractive lithium niobate crystals by the combination of light-induced space-charge fields with externally applied electrical fields. In terms of our stochastic model, the probability for domain nucleation is modulated according to the sum of external and internal fields. The model describes the shape of the domain pattern as well as the effective degree of modulation. [ABSTRACT FROM AUTHOR]

In piezoresponse force microscopy a lateral signal at the domain boundaries is occasionally observed. In recent years, a couple of experiments have been reported and varying explanations for the origin of this lateral signal have been proposed. Additionally, elaborated theoretical modeling for this particular issue has been carried out. Here we present experimental data obtained on different crystallographic cuts of LiNbO3, BaTiO3, and KTiOPO4 single crystals. We could thereby rule out some of the explanations proposed so far, introduce another possible mechanism, and quantitatively compare our results to the existing modeling. [ABSTRACT FROM AUTHOR]

Trimerization-polarization domains in ferroelectric hexagonal YMnO3 were resolved in all three spatial dimensions by piezoresponse force microscopy. Their topology is dominated by electrostatic effects with a range of 100 unit cells and reflects the unusual electrostatic origin of the spontaneous polarization. The response of the domains to locally applied electric fields explains difficulties in transferring YMnO3 into a single-domain state. Our results demonstrate that the wealth of nondisplacive mechanisms driving ferroelectricity that emerged from the research on multiferroics are a rich source of alternative types of domains and domain-switching phenomena. [ABSTRACT FROM AUTHOR]

Trimerization-polarization domains in ferroelectric hexagonal YMnO3 were resolved in all three spatial dimensions by piezoresponse force microscopy. Their topology is dominated by electrostatic effects with a range of 100 unit cells and reflects the unusual electrostatic origin of the spontaneous polarization. The response of the domains to locally applied electric fields explains difficulties in transferring YMnO3 into a single-domain state. Our results demonstrate that the wealth of nondisplacive mechanisms driving ferroelectricity that emerged from the research on multiferroics are a rich source of alternative types of domains and domain-switching phenomena. [ABSTRACT FROM AUTHOR]

Given that a ferroelectric domain is generally a three dimensional entity, the determination of its area as well as its depth is mandatory for full characterization. Piezoresponse force microscopy (PFM) is known for its ability to map the lateral dimensions of ferroelectric domains with high accuracy. However, no depth profile information has been readily available so far. Here, we have used ferroelectric domains of known depth profile to determine the dependence of the PFM response on the depth of the domain, and thus effectively the depth resolution of PFM detection. [ABSTRACT FROM AUTHOR]

At first sight, piezoresponse force microscopy (PFM) seems an ideal technique for the determination of piezoelectric coefficients, thus making use of its ultrahigh vertical resolution (<0.1 pm/V). In general, however, only qualitative PFM imaging is performed and in the few publications containing quantitative data, the obtained values vary considerably with respect to macroscopic measurements. In this contribution, we present a reliable calibration procedure for PFM followed by a careful analysis of the encounted difficulties using PFM for determining piezoelectric coefficients. We point out different approaches for their solution and expose why those difficulties cannot be circumvented without an extensive effort. [ABSTRACT FROM AUTHOR]

The contrast mechanism for ferroelectric domain imaging via piezoresponse force microscopy (PFM) is investigated. A vectorial description of PFM measurements is presented which takes into account the background caused by the experimental setup. This allows a quantitative, frequency independent analysis of the domain contrast which is in good agreement with the expected values for the piezoelectric deformation of the sample and satisfies the generally required features of PFM imaging. [ABSTRACT FROM AUTHOR]

The contrast mechanism for the visualization of ferroelectric domain boundaries with lateral force microscopy is generally assumed to be caused by mechanical deformation of the sample due to the converse piezoelectric effect. We show, however, that electrostatic interactions between the charged tip and the electric fields arising from the surface polarization charges dominate the contrast mechanism. This explanation is sustained by quantitative analysis of the measured forces as well as by comparative measurements on lithium niobate and potassium titanyl phosphate. [ABSTRACT FROM AUTHOR]