AFM characterization of domain structure of ferroelectric TGS crystals on a nanoscale

Atomic force microscopy has been used for the study of the surface topography and domain structures of triglycin sulfate (TGS) crystals. The images of various types of domains at the polar (0 1 0) surfaces of as-cleaved TGS crystals have been obtained (in contact mode and resonant mode). The crystals grown old, after annealing, gamma-irradiated by various doses, were studied. It has been found that the surface relief of crystals after annealing differs from that of crystals grown old and irradiated: in the first case the peak-to-peak value is nearly constant whereas in the second case it varies in wide limits. The parameters of domain structure were determined. These parameters have been shown to be different for crystals grown old, crystals after annealing and irradiated crystals. It has been shown that, after cantilever scanning after a long period in different AFM modes the TGS surface experiences a partial polarization reversal.     

Atomic Force Microscopy as a Universal Means of Measuring Physical Quantities in the Mesoscopic Length Range

Data are given on recent advances in atomic force microscopy, which is used in precision measurements of various physical quantities and fields at solid surfaces. New designs are considered for micromechanical cantilevers, which are used as physical, chemical, and biological sensors.     

Electron capture in intermediate-to-fast heavy ion collisions with neutral atoms

Electron capture processes of heavy ions, like Ge^q+, Xe^q+, Pb^q+, and U^q+, respectively, with the charge q ≈ 10–40, occurring in collisions with gaseous targets are considered in the E = 0.1–100 MeV/u projectile energy range. Calculations of single-electron capture cross sections are performed using the CDW and the CAPTURE computer codes. These are compared with available experimental data and CTMC (Classical-Trajectory Monte Carlo) calculations. Although the overall agreement is found to be within a factor of two, in some cases of heavy many-electron projectiles, e.g., U²⁸⁺ + N₂, Ar collisions, experimental cross sections at high energies are far smaller than theoretical predictions. Moreover, for these collision systems the observed energy dependencies are quite different from each other. Possible reasons for this behavior and how the theoretical models can be improved are discussed.     

Clean boxes with artificial climate for atomic force microscopy: New possibilities for diagnostics of nanodimensional objects

A clean box with an artificial climate is developed and designed to increase the accuracy of measurements by atomic force microscopy in the air and to improve the reproducibility of the results of diagnostics of the surface. The main functions of the box are the provision and maintenance of the temperature and humidity in the working zone with a high degree of accuracy and in various combinations. The main technical characteristics of the box are presented. The main advantages of operation under the conditions of an artificial climate are analyzed. It is shown that the special procedures give the possibility to eliminate the distorting effect of the static electricity on the surface under investigation and, specifically, to remove the already accumulated charge and prevent its appearance in the course of the experiment. The use of the suggested procedures allows one to correctly describe the specific features of the surface topography of dielectrics at the microscopic and nanoscopic levels.     

One-electron capture and target-ionization in He-neutral-atom collisions

One-electron capture and target-ionization cross-sections in collisions of He⁺ ions with neutral atoms: He⁺ + A → He + A⁺ and He⁺ + A → He⁺ + A⁺ + e, A = H, He(1s², 1s2s), Ne, Ar, Kr, Xe, are calculated and compared with available experimental data over the broad energy range E = 0.1 keV/u–10 MeV/u of He⁺ ions. The role of the metastable states of neutral helium atoms in such collisions, which are of importance in plasma physics applications, is briefly discussed. The recommended cross-section data for these processes are presented in a closed analytical form (nine-order polynomials) which can be used for a plasma modeling and diagnostics.     

Space Surface Parameters Determined from Fourier Transforms in Atomic Force Microscopy

A tabular analytic method for calculating space surface parameters of different materials is suggested. It uses Fourier transforms obtained with an atomic force microscope. Examples of calculation are given for periodic space structures and surfaces with different degrees of anisotropy and periodicity. It is shown that space parameters, namely, texture direction and texture direction index and also radial wavelength and radial wavelength index, allow anisotropy characterization and periodicity determination at a nanometer scale.