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Germanium whiskers can be grown on gold plated germanium substrates by thermal decomposition of GeH 4 in a closed growth vessel designed for visual observation. Structure of whiskers changes in the order of amorphous, poly-crystalline and single crystal whiskers with raising the substrate temperature from 300 to 600°C or decreasing the pressure of a mixture gas (5%GeH 4 +95%Ar) from 300 to 50 Torr. With regard to amorphous whiskers, the rate of elongation at the beginning of the growth period is proportional to the pressure of the mixture gas. Two mechanisms, elongation and thickening, are controlled by entirely different activation energies 0.60 and 0.95 eV, respectively.

The thermal conductivity of liquid 3 He has been measured at pressures 1.30, 10.0, 20.0 and 27.0 kg w/cm 2 and at temperatures from 300 mK down to 20 mK. For each pressure, the coefficients of thermal conductivity in the limit T →0, and the finite-temperature corrections to the limiting low-temperature behavior of normal Fermi liquid were obtained. The results were compared with the Rice's transport theory in nearly ferromagnetic Fermi liquid. Though qualitative agreement was obtained for the temperature dependence of the coefficients, the observed pressure dependence was stronger than that predicted by the theory.

Magnetic interaction between two π orbitals in D ∞ h symmetry is discussed using an effective Hamiltonian set up mainly from symmetry consideration. The resonance effect between orbital structures π a + π b - and π a - π b + is found most important in determining the ground state ( 3 Σ g - ) of the system. The obtained energy levels give a good description of the ground and lower excited states of the O 2 molecule, so that the magnetism of O 2 can be explained by the valence bond theory only with correct care of the orbital valence. It is also shown that the same resonance effect makes 1 Σ + state of the π-π 3 system ( e.g. , CO molecule) most stable. The effective Hamiltonian for a p - p system with D ∞ h symmetry is derived in a similar way. With t 2 - p isomorphism, the results reduce to the restricted form given recently by Drillon and Georges when several relations are assumed to hold among the parameters.

Nuclear magnetic susceptibility and Zeeman-exchange relaxation time T Z X of solid 3 He have been measured by pulsed NMR method using Pomeranchuk cooling technique between 15 mK and 0.97 mK in a static field of about 70 gauss. Magnetic transition to the antiferromagnetic phase was observed at 1.00 mK where the susceptibility decreased to 42% of its maximum value. This drop in susceptibility coincides with the abrupt leveling of 3 He pressure in cooling process which shows thermodynamically a phase transition due to abrupt decrease of solid 3 He entropy. The magnitude of T Z X is consistent with the one estimated from BPP (Bloembergen-Purcell-Pound) theory, but the observed temperature dependence can not be explained on this basis.

The phase separation curve of dilute solution of 4 He in liquid 3 He has been studied using a sensitive dielectric technique and a film-flow-tight valve attached to a cell. The solubility of 4 He at low temperatures was larger than the value expected from the equation proposed by Saam et al.

An anomaly has been found in the current-voltage characteristics of the electron tunnelling in a cross type Sn-SnOx-Pb junction with a small tunnelling resistance and a very thin tin film, which was proved to correspond to the superconducting-to-normal transition in the tin film. Some properties of the anomaly were also examined. It is pointed out that as the electron tunnelling method requires relatively large current through the junction with a small tunnel resistance in order to measure the energy gap directly, the superconducting state of a very thin film is disturbed by this tunnel current.

The polarized reflectivity spectra are measured on the oriented films of (SN) x by the synchrotron radiation. From the Kramers-Kronig analysis of the spectra, we demonstrate quasi-one-dimensional behaviours of electronic states around the Fermi level. Observed spectrum for E // b is in a good agreement with the theoretical curve calculated by Grant et al. on the OPW band structures, but there is a considerable discrepancy between the experimental and theoretical curves for E ⊥ b .

Amorphous silicon whiskers have been grown in an atmosphere composed of SiH 4 (5%) and argon (95%) at around 650°C. Time-lapse sequence of the growth of whiskers is presented in this report. By using an optical system, it has been observed that the growth proceeds at their tips.