The effects of accelerating voltage and collection angle on the mean free path for all inelastic electron scattering (λ_p), which is an important parameter for determining specimen thickness by using electron energy‐loss spectroscopy, were investigated with crystalline Si and amorphous SiO₂. First, thickness of Si film was measured with the convergent‐beam electron diffraction method, while thickness of SiO₂ particles was estimated from their spherical shape. Then from electron energy‐loss spectra, λ_p was evaluated for Si film and SiO₂ particles by changing the accelerating voltage (100∼300 kV) and the collection angle for the scattered electrons. Under the condition of no objective aperture, λ_p for Si film and SiO₂ particles was found to increase with the increase of accelerating voltage and to take values of 180 ± 6 nm (Si) and 247 ± 8 nm (SiO₂) at 300 kV. Also, it was found that λ_p in both cases decreases drastically with the increase of collection angle in the range smaller than 25 mrad, while it tends to take a constant value at the collection angle larger than 25 mrad at 200 kV.

The double-probe piezodriving specimen holder that was recently developed by some of the present authors is modified to introduce a laser irradiation port in one of its two arms. As a result, the new specimen holder consists of a piezodriving probe and a laser irradiation port, both of which can be three-dimensionally controlled by using piezoelectric elements and micrometers. While the piezodriving probe interacts with the specimen set in the holder in several ways, the laser beam causes photo-induced phenomena to occur. By performing electron holography using the new specimen holder, we demonstrate that it is possible to evaluate the change in the electric field resulting from the discharging effect of laser irradiation on organic photoconductors.

By means of electron holographic visualization of detailed electric potential distribution around sciatic nerve tissues coated with C and OsO₄, we show that the steady state of these specimens subjected to intense charging with electron irradiation is accompanied with a dynamic motion of collective secondary electrons; the secondary electrons emitted from the coated specimens revolve around the positively charged specimens forming stationary orbits. Further, this study clarified the possibility of the direct visualization of a part of the orbits of the collective secondary electrons without disturbing their motions.

Thickness measurements of diamond-like carbon (DLC) films by electron energy-loss spectroscopy (EELS) and electron holography are discussed. In order to evaluate the thickness by EELS and electron holography, the mean free path for inelastic scattering and mean inner potential of DLC films were determined precisely, respectively. It is found that both the mean free path for inelastic electron scattering and the mean inner potential are sensitive to the preparation methods, namely the density of DLC films. The present work has demonstrated that thickness measurement by EELS is available to DLC films thicker than 20 nm, while electron holography can be applied to thinner films (∼5 nm). Furthermore, close relations are observed between the density of DLC films and the energy-loss spectra.

The magnetic structure of a ${\mathrm{Nd}}_4{\mathrm{Fe}}_{77}{\mathrm{Co}}_3{\mathrm{B}}_{16}$ two-phase nanocomposite is studied by Lorentz microscopy and electron holography in this article. The big domains consisting several grains show strong intergranular exchange interaction. Some bright spots inside domains reflect a nonuniform magnetic structure that is characterized as a magnetic vortex using electron holography. It results from the strong intergranular exchange interaction and the randomly oriented ${\mathrm{Nd}}_2{\mathrm{Fe}}_{14}\mathrm{B}$ particles. This nonuniform magnetic structure is extensive in two-phase nanocomposites, and has an important influence on the magnetic properties. The internal stray field is dramatically weakened because of the zero divergence of magnetization in the magnetic vortex, and small $N_{\mathrm{eff}}$ is observed. With the numerical simulation, it is found that the formation of the magnetic vortex induces a concave demagnetization curve and decay of the coercivity. This is the reason why the coercivity of practical magnets deviates greatly from that of theoretical results.