We have widely investigated the synthesis of single crystal of LaB6 and its properties, e. g. bonding nature, electronic structure, surface and thermionic emission characteristic, which is well-known as a cathode material. The single crystals were successfully prepared, using a floating zone technique. It is suggested from XPS, 11B NMR and Raman scattering etc. that the B-B interaction is covalent and the ionic M-B interaction is reduced by the shielding effects of conduction electrons. The dHvA effect indicates that the Fermi surface consists of a connected surface centered at the point X. It is pointed from various surface investigations that the origin of the low work function is probably electronic dipole moments induced by surface La ions. Also, the characteristics of single crystal cathode are discussed.
A review of a familiar III-V compound semiconductor, InSb, is made from two stand-points of view: electronic materials science and solid state physics. First, bulk-material char-acterization, electron mobility at 77K and residual impurities, is briefly discussed to see the present stage of purification and crystal perfection. Second, wafering-processes, thin films, anodic oxidation and ion implantation techniques are reviewed on the basis of our experimental results. Third, negative longitudinal magnetoresistance, magnetophonon resonance, magneto-plasma and magnetic dipole resonances, and two dimensional transport phenomena are disussed in conjunction with crystal preparation conditions. Finally, two new developments in device applications, CID imaging array and SFR laser, are described.
The method of realizing the triple point of oxygen which was previously reported is reexamined. Different kinds of triple point cells are classified, and also the process of temperature equilibrium is analyzed mathematically. The errors of the triple point arise from the heat leaks, heat to be transfered to the thermometer after it has reached the triple point temperature, and the chemical impurities of the sample. In the previously reported cell, however, the heat leaks not occur as the thermometer is enclosed within the solid sample. It enables us to take the melting curve in a short time while the impurities are still frozen. The impurity correction is, thus, easily found.
In this paper, an analysis is made on the method of focusing zoom lenses whose front part consists of two movable and one fixed members. Tne following results are obtained. (1) For a given object distance, an analytical representation is given on the amount of movement needed for the system to be in focus. (2) With the help of the set theory, a classification of focusing systems is established. The result shows that the model treated in this paper contains 54 kinds of focusing systems. (3) One of the new focusing systems derived from the analysis is presented together with its numerical data.
A method of evaluating curves of thermally stimulated current determined experimentally is described. This is essentially one of curve fitting, and serves to determine the energy depth of traps from the excellent fit eventually obtained between the theoretical and experimental curves. In addition to the equation for TSC with constant heating rate βc, an equation with heating rate β(T) of exponential form is derived. A numerically calculating technique is developed with application to some experimental results in anthracene single crystals excited by Q-switched ruby laser. Theoretically numerical calculation is performed for the previously reported second group within the numerous experimentally observed peaks of TSC. The energy depth Et for this trap is evaluated to be about 0.57 eV and that the trap in anthracene single crystals is a monoenergetic state of slow retrapping nature is confirmed. The results of calculation on the effect of measured temperature error on the Et value is also reported.
The present situation of investigation on crystallization of amorphous alloys and metastable phases is reviewed. Metastable phases, i.e. crystallization products, are classified into two categories: one contains metastable crystals with new atomic arrangements, almost all of which remain yet unsolved, and the other is that which may be called topologically metastable structures and in which stable (or metastable) crystals arrange themselves in novel manners. Some of them may have excellent properties suitable for practical applications. Methods of analysis of the crystallization kinetics, mainly by differential scanning calorimetry, are explained, and many experimental approaches to study the structural changes in atomic scale by X-ray diffraction, electron microscopy and electron diffraction are described.