Sadaaki Yanagawa

Influence of the Free Crystal Surface on the Heisenberg Ferromagnet

The influence of the free crystal surface on the Heisenberg ferromagnet, which has nearest-neighbour exchange interactions, has been considered using the double time Greens functions. The existence of the surface on which atomic spins have different exchange integrals and g -factors from those of bulk spins is shown to have a possibility of giving rise to a new mode which is localized in the vicinity of the surface. The free surface also introduces the new correction term to the low temperature magnetization and specific heat which are otherwise both proportional to T 3/2 . This correction is proportional both to the temperature and to the area of the surface and is shown to be detectable when the crystal has a proper size and thickness.

Theory of the Normal Modes of Vibration in Crystal

The normal modes of vibration in crystal have been determined by the group-theoretical method, familiar in the theory of molecules. Se<:tit~t !!q:uation [or determining: the frequencies of normal modes has been reduced to lower degrees by making use of the translational; crystal and K-groups. The fraquency-distribution curves have been obrained [or a few types of crystals, with a brief reference to 2nd order Raman-elfect.

Influence of a free crystal surface on a ferromagnetic spin system

Abstract It is shown that the specific heat and the magnetization of a ferromagnetic spin system which has a free crystal surface are proportional to T in the low temperature limit.

Effects of Bremsstrahlung on the Linear Absorption Coefficient for Relativistic Electron Diffraction

The effect of the inelastic scattering by Bremsstrahlung is calculated between 10 KeV and 2000 KeV of the energy of the incident beam. The absolute value and the β(= v / c )-dependence of µ 0 -1 is evaluated numerically, and it is shown that the effect considered here is much small as compared with one of the electronic excitation.

On the Ground State Spin of Ti47 and Mn55

Lawson and Uretsky have shown that it is possibie to compute the energy splittings for the configuration by making use of the excitation energies for the (f/sub 7/2)/sup plus or minus 2/ (f,/sub 7/2//sup 4/ given by experimental measurements in nuclei with (f,/sub 7/2/)/sup n/ protons and 28 (closed shell) neutrons. Talmi has also taken the same procedure in nuclei with (f,/sub 2/7/)/ sup n/ neutrons and 20 (closed shell) protons. In these nuclei it may be noted that the energy splitting E(2) between the first excited state and the ground state for (f /sub 7/2//sup plus or minus 2/) shows a nearly constant value; 1.4 to 1.6 Mev. Thin regularity would give a more sensitive effect to lowering the state (7/2) than the state (5/2) of nuclei for (f,/sub 5/2/)//sup plus or minus 3/ configuration; (Ca/sup 43/, Ca/sup 45/, V/sup 51/, and Mn/sup 53/). A summary of calculations together with the known experimental information is tabulated.

Contribution of the metal surface to the Landau diamagnetism

Abstract Modification of the ordinary Landau diamagnetism due to the surface is calculated for a semi-infinite metal. By using the second Born approximation it is found that the magnetic surface levels induce a small but positive contribution to X .