Thermal Insulating Properties of Carbonized Corkboard and Layered Metal Sheets at Low Temperatures

(1) Thermal conductivity of carbonized corkboard and layered aluminium sheets has been measured at the temperature range from room temperature to -60°. (2) The conductivities of both materials cited above show remarkable monotonous decrease as the temperature is lowered. (3) If the similar construction of the aluminium sheets layer as that cited in this paper is adopted, the heat insulating property of that layer will be almost the same as that of carbonized corkboard., as it is easily apprehended by comparing the data given in Tables 1 and 3. (4) When tin sheets have been used in place of aluminium sheets almost the same results could be obtained

Electrical Resistivity and Hall Effect of Noble Metals at Very Low Temperatures

The electrical resistivity and the Hall effect of gold, silver and copper were measured at low temperatures. The Hall effect of gold which showed the minimum at 6°K in the resistivity-temperature curve was found to be dependent on temperature below 6°K. Since the electron mobility deduced from the resistivity and the Hall coefficient was nearly constant at temperatures below 6°K, it was suggested that the origin of the resistance minimum might be ascribed to the change in the concentration of current carrier. On the other hand, the silver and copper specimens showed the normal behaviour of electrical resistivity and the temperature-independent Hall effect. In general, the Hall coefficients of these noble metals were found to be constant at low temperatures, the values being about 20 per cent larger than those at room temperatures, which fact indicates that the Hall effect is temperature-dependent at intermediate temperatures (20～300°K)

Specific Heat of Tellurium and Selenium at Very Low Temperature

The specific heat of tellurium and selenium was measured in the range of liquid helium temperatures. The measurements were made with a calorimeter of Nernst-Eucken\u27s type. A carbon composition resistor, having a nominal room-temperature resistance of ten ohms, was used as the suitable thermometer in this temperature region. It was found that the observed values of the specific heat of these metals did not consist of the electronic specific heat but only of the lattice one which is proportional to T^3. Discussions were given of the specific heat of these metals at low temperatures from the viewpoint of the anisotropy of the chain-like crystal lattice

On the Vibrational Spectrum and the Vibrational Specific Heat of a Binary Superlattice Alloy

The change in the vibrational modes of a binary superlattice alloy due to the change in its own degree of order has previously been discussed. It was then expected that the vibrational specific heat of the superlattice alloy would change in response to the change in its own degree of order. Using the result obtained formerly, we have applied, in the present paper. Houston\u27s approximate method of finding the frequency distribution function N(ν) to the calculation of the vibrational specific heat of β-brass in the state of any specified degree of order. It is shown that the vibrational specific heat of the disordered alloy is generally larger than that of the ordered one at oridnary temperatures. If two kinds of atoms which are the components of alloy are nearly equal in mass, the vibrational specific heat of the ordered alloy becomes larger than that of the disordered one at low temperatures

Transverse Galvanomagnetic Effect of Bismuth Single Crystal in a Strong Magnetic Field

Transverse galvanomagnetic effects of bismuth single crystal are measured in a strong magnetic field up to about 100 kilo Oersted at 4.2, 3.0 and 1.8K. And the twelve components of the galvanomagnetic tensor are obtained with respect to the magnetic field dependence. Furthermore the behaviors of the galvanomagnetic tensor components near the quantum limit of the magnetic quantization are studied, expecting that they can lend themselves to analyse the energy band structure. In a strong magnetic field, the amplitudes of the oscillatory part of the galvanomagnetic tensors are nearly temperature independent, and the behaviors of Hall effect appear to be different from the expected one from the classical theory of the two bands model

On the Electromagnetic Properties of Single Crystals of Tellurium. II : Ettingshausen-Nernst Effect

The Ettingshausen-Nernst effect of a single crystal of highly purified tellurium has been measured over the temperatures ranging from -160 to +300℃. In the intrinsic semiconductor range of temperature, it was found that the value of coefficient of this effect is roughly in agreement with that evaluated theoretically from the values of the electron and hole mobilities and the width of the forbidden region, which were deduced by analysing the experimental values of the conductivity, the Hall coefficient and the magneto-resistance coefficient measured on the same specimen

The de Haas-van Alphen Effect of Zinc

The de Haas-van Alphen effect of pure zinc crystal was investigated at temperatures ranging from 63°to 1.3°K by means of a torsion magnetometer. In the magnetic field less than 16 kilo-oersted and at the temperatures 4.2°K and above, a remarkable periodic variation of magnetic susceptibility was found with the intensity of magnetic field and it is here referred to as the long-period effect. While in the field higher than 19 kilo-oersted and at temperatures from 4.2°to 1.3°K, it was observed that a shorter-period and smaller-amplitude effect, which is accompanied by some complicated beat structures, is superposed on the high field extension of the long-period effect just cited. From the analysis of the long-period effect, we obtained the next de Haas-van Alphen parameters : E_=5.5×10^ erg, m_/m_0=5.4×10^, m_/m_0=2.7×10^, T_=400°K, n_l=1.2×10^atom^; and from the analysis of the short-period effect, we got : E_=7.9×10^ erg, m_/m_0=1.6×10^, m_/m_0=8.3×10^, T_=570°K, n_s=3×10^ atom^

The Measurement of the Young\u27s Modulus of Metals and Alloys by an Interferometric Method. III : The Influence of Heat-Treatment on the Young\u27s Moduli of Fe-Al Alloys, and the Young\u27s Moduli of Ni-Al, Al-Cu Alloys and German Silver in the Annealed State

The measurement described in the earlier papers of this series has been extended to the study of the influence of heat-treatment on the Young\u27s moduli of Fe-Al alloys having the composition up to 14.75 per cent aluminium. It becomes clear that the Young\u27s modulus of ordered Fe_3Al (13.8 per cent aluminium) is smaller than that of disordered one. This result is contrary to the cases of Cu_3Au and Ni_3Mn. Moreover, measurement has been done on the static Young\u27s moduli of Ni-Al alloys (up to 5.17 per cent aluminium), several specimens of Al-Cu alloys and german silver. The Young\u27s modulus vs. composition curve of Ni-Al alloys seems to be akin to the curve peculiar to Ni-alloys, such as Ni-Cu and Ni-Mn systems

Electrical Properties of P-Type Indium-Antimonide

Electrical properties of P-type InSb from ambient to liquid helium temperatures are measured and several parameters associated with the charge carriers are obtained

Magnetic Flux Jumps in Superconducting 3Nb-Zr Alloy Wires

The magnetic field strength in the center of three kinds of superconducting solenoids wound with 3Nb-Zr alloy wire was measured through the course of a gradual variation of the external magnetic field. The manner of a discontinuous change of a magnetic field, viz. the flux jump which gives a clue to clarify the behavior of penetration and trapping of magnetic filaments through the solenoid was studied. In general, the step height of flux jumps becomes smaller as the external magnetic field becomes stronger