Physical properties of tellurium have been investigated by making use of various experimental methods. The samples were prepared mainly with Bridgman method. The handedness of the crystal has been determined from the investigations of the asymmetric etch pits on the cleaved faces of tellurium. The chemical shift tensors of tellurium and selenium have been derived from the anisotropic chemical shift observed in the nuclear magnetic resonance in these materials. The structure of the valence band and the impurity levels of tellurium have been investigated in detail by means of far-infrared cyclotron resonance, infrared absorption and inter-valence band magnetoabsorption, and the parameters of the valence band of tellurium have been determined precisely. The interband magnetoabsorption has also been observed in tellurium and excitonic effects have been found. The galvanomagnetic properties of tellurium with various hole concentrations have been investigated in the temperature range from 0.05K to 77K under the magnetic field up to 100 kOe. It was found that the behaviours of the undoped samples were quite different from those of the Sb-dopes samples. Anomalous temperature dependences of the conductivity and the Hall coefficient observed below liquid helium temperature in the undoped samples have been explained by introducing a new kind of two carrier model. The phonon-assisted tunneling effect has been found in Te-TeO2-Pb tunneling junctions. The observed phonon energies are in good agreement with those obtained from other experiments. The Raman scattering by the phonons has also been observed in tellurium, which shows the polarization dependence predicted theoretically.
A new type of low energy electron diffraction apparatus was constructed which is feasible for Auger electron energy analysis. The apparatus is composed of a fluorescent screen and four mesh electrodes of hemi-spherical form. By use of the apparatus, cleaning and adsorption of gases on the (110) face of tungsten crystal were investigated from observation of the LEED pattern as well as measurement of the Auger electron spectrum. Characteristics of energy resolution of the repelling electrodes was sufficiently sensitive to detect a small Auger peak at the initial stage of gas adsorption. Under the condition of controlled gas adsorption, it is confirmed approximately that there is a linear relation between the surface coverage of gas and the peak height of Auger electrons.
This paper describes the experimental results on the deformation of a photographic plate caused by practically imperceptible variations in humidity due to air-turbulence. The deformation was detected by a real time holographic interferometer. The deformation deteriorates the reconstructed image of a hologram, especially, that of a Lippmann type hologram. Its effects on the reconstructed image are discussed theoretically and experimentally. Several methods to prevent the deformation, when a photographic plate is used in holography, are discussed.
A novel acoustic surface waveguide is proposed. Differences between the velocities of acoustic surface waves in polarized regions of ferroelectric materials and those in unpolarized regions were used for the waveguides. In the theoretical analysis, it is assumed that the guide is a sandwich structure, consisting of two kinds of isotropic materials. Using the same boundary conditions as those for a thin film guide, the characteristic of the guide was calucalated. Experiments on the transverse tightness of binding and dispersion for waveguides were performed at 5.2 to 5.8 MHz, using P. Z. T. ceramics for such ferroelectrics. The experimental results were semiquantitatively in agreement with theoretical results. The excited mode in the experiments was the lowest symmetric mode. The properties of the device, which are influenced by an external electric field, may be of interest for use in memory and switching devices.
The cross-sectional structure of evaporated Bi films has been investigated electron-microscopically by means of the replica technique. Films were prepared changing the evaporation conditions : substrate temperature, residual gas pressure and deposition rate. The influence of deposition rate appears most conspicuously at the thickness where the film becomes continuous : the structure of the film surface is essentially determined at this stage. The influence of deposition rate becomes more and more remarkable as the substrate temperature is elevated. If the residual gas pressure is high, the colmnar growth, as was observed with Al films, takes place in Bi films, also.
A usual fast neutron time-of-flight spectrometer was extended to receive the signals from two detectors by providing a few additional electronic circuits. A memory location encoder shares the outputs from the two detectors to their respective 256 channel memory locations of an 1024 channel PHA. The present method can be applied to a multi-detector system.
This paper describes a high precision thermostat designed in our laboratory. In the usual thermostat, the temperature of water in the bath is, in general, controlled by a regulating electric heater. In our apparatus the bath temperature is regulated by using many electric bulbs instead of the usual resistance wire. Since the radiation energy from the bulbs is supplied uniformly and quickly to the water in the bath, it is possible to keep the temperature of water at the desired temperature within a deviation of ±0.001°C.