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One can correct spherical aberration in a transmission electron microscope by using a newly developed aberration-correction method involving off-axis electron holography. In this method, a liquid-crystal spatial-light modulator (LC SLM) is employed during the holographic reconstruction step to compensate for spherical aberration. Application of this method to high-resolution off-axis electron holograms of fine gold particles is presented. The phase distribution of the corrected object wave is visualized by the Zernike phase-contrast method carried out with the same LC SLM. Key words: Off-axis electron holography, spherical aberration correction, liquid-crystal spatial-light modulator, Zernike phase contrast, high-resolution observation.

An algorithm exhibiting excellent precision and spatial resolution when determining electron phase distribution in a transmission electron microscope described a phase-shifting interferometry. This method, which did not impose limitations on the phase shifter and data acquisition, made the interferometry more versatile. The phase distribution was accurately determined when the initial interferogram phase was computed from the interferogram itself.

Three-dimensional magnetic vector fields are reconstructed using electron-holographic interferometry. The magnetic flux distributions are based on the two-dimensional phase distributions of the electron wave and are developed using an algorithm. The method is illustrated in a barium ferrite particle.

A method for correcting the aberration of an electron-objective lens during the holographic reconstruction stage is proposed. In this method, a liquid-crystal spatial-light modulator is used as a computer-controlled phase plate on the Fourier plane of an optical reconstruction system. The effective refractive index of the liquid crystals changes with the applied electric field because of the crystal's birefringence. Thus the phase of light passing through the liquid-crystal spatial-light modulator can be flexibly modulated to compensate for wave aberration. Experimental results on adjusting the focus of the image wave reconstructed from an electron-image hologram of magnesium oxide particles are presented.

A method of reconstructing the three-dimensional electric-potential distribution of a microscopic object with electron-holographic interferometry is presented. A sequence of processing techniques is developed to obtain the projected phase proportional to the potential distribution. A modified backprojection algorithm is used to reconstruct a three-dimensional potential distribution from the projected potentials obtained at different projection directions. In an experiment this method is applied to reconstruct three-dimensional latex particles.

The wave nature of electrons is utilized through electron holography to directly observe magnetic flux lines, as an electron interference micrograph, with a 'coherent' field-emission electron beam. This technique is applied to magnetic domain structure observation of a ferromagnetic thin film and also to the direct observation of flux lines penetrating a superconducting thin film.

A description is made of a grating optical system for extracting phase distribution from electron holograms, that has an extremely high stability and can eliminate system aberrations. Phase measurement is achieved with phase-shifting interferometry by stepping the grating laterally. The system is used to extract the phase distribution of a magnesium oxide crystal from its electron hologram.

REBaCuO (RE: rare earth) bulk superconductors, whose microstructures can be controlled by quench and melt growth (QMG) processing, have a high critical current density Jc, which makes them well suited for use in practical applications. Through a combination of electron holography and a focused ion-beam technique, we succeeded in visualizing a fluxon pinned by an insulating particle in a QMG bulk Y-Ba-Cu-O superconductor. We also clarified the magnetic flux distribution in the vicinity of the insulating particles at different temperatures in a uniform external magnetic field. [ABSTRACT FROM AUTHOR]

Triple-biprism electron interferometry has been developed to flexibly control all interference parameters, i.e., interference region (size and shape), fringe spacing, and fringe angle. Each filament electrode of the upper and middle electron biprisms is installed in the individual image planes of the objective and first magnifying lenses, respectively. One more filament electrode of the lower biprism is set between the crossover plane and image plane behind the second magnifying lens. The azimuth angle between the upper and middle filaments is set at 90°, and lower filament is set at about 45° for both of the above filaments. Among many possible optical setups, we chose the setup with the easiest and most flexible control of all the interference parameters through theoretical investigation and experimental confirmation. The interferometer was constructed in a 1×106 V field emission electron microscope, and the overall performance was demonstrated and investigated experimentally. [ABSTRACT FROM AUTHOR]

High-resolution electron holography has been achieved by using a double-biprism interferometer implemented on a 1 MV field emission electron microscope. The interferometer was installed behind the first magnifying lens to narrow carrier fringes and thus enabled complete separation of sideband Fourier spectrum from center band in reconstruction process. Holograms of Au fine particles and single-crystalline thin films with the finest fringe spacing of 4.2 pm were recorded and reconstructed. The overall holography system including the reconstruction process performed well for holograms in which carrier fringes had a spacing of around 10 pm. High-resolution lattice images of the amplitude and phase were clearly reconstructed without mixing of the center band and sideband information. Additionally, entire holograms were recorded without Fresnel fringes normally generated by the filament electrode of the biprism, and the holograms were thus reconstructed without the artifacts caused by Fresnel fringes. [ABSTRACT FROM AUTHOR]

A combination of the standard transmission and scanning electron microscope techniques is employed to explain the crystalline structures of the different permalloy narrow wires. The crystalline grains are shown to grow larger in the current region around the Curie temperature.

Introduces a developed application of electron holography to magnetic domain structure observation. Background on electron holography; Information on electromagnetism; Methods used in the formation of the electron holography.

Examines the sensitivity-enhanced electron holography and its application to magnetic recording investigations. Information on the quantitative measurement of magnetic flux; Distribution of a leakage magnetic field; Calculation of the magnetic field vector component.

In the phenomenon known as the Aharonov-Bohm effect, magnetic forces seem to act on charged particles such as electrons--even though the particles do not cross any magnetic field lines. Is [...]