The magnetic moment of the 3⁺ second excited state at 417 keV in ²⁶Al has been determined by a time integral perturbed angular distribution method. This level was populated by the ²⁵Mg(p, γ)²⁶Al reaction at E_p=956 keV. An external field of 34.1 kOe was applied perpendicular to the reaction plane. The Larmor precession angle Δθ was derived from the difference of rotation angles between the angular distributions of the 417 keV and the 1650 keV γ-rays emitted in the reaction. The mean life of the 417 keV level was carefully remeasured to be τ=1.72±0.02 nsec. Combining the precession angle Δθ with the mean life τ the g-factor of this level was determined to be g=0.65±0.15. This value is consistent with both the shell model and the Nilsson model calculations.

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NMR line shape and spin lattice relaxation time of solid hydrogen are measured at 22 MHz for the fractional ortho content of 0.55>X>0.08 and temperature range of 1 K>T>0.2 K. As the sample temperature decreases below 0.35 K, the absorption line changes from singlet to doublet. The phenomenon is observed at ortho contents as small as 0.08. The critical temperature (T^*), below which the line exhibits the doublet structure, weakly depends on X and is expressed as T^*=(0.3±0.1)(X+0.5) K (0.55>X>0.08). The spin lattice relaxation time (T₁) is found to show an anomalous increase by a factor of 10² at T\simeqT^*. The increase of T₁ with decreasing temperature below T^* gives Δ_L=0.25±0.05 K for the lower edge of the excited state with J_z=±1. Temperature dependence of the field separation of the doublet line is analyzed by using the order parameter formulated by Ueyama and Matsubara. The result gives Δ=1.0±0.2 K for the mean energy gap between the rotational substate with J_z=0 and J_z=±1.

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A critical dynamics of the polyorientational phase transition is presented, which is an extension of the statistical equilibrium theory in random phase approximation previously given by one of the authors. In the approximation of the linear theory, a relaxation equation for the critical slowing down as well as a formula for the dynamical susceptibility tensor are derived. The present theory covers Matsubara’s one for the X-ray scattering by orientationally disordered crystals in the thermal equilibrium limit, and reduces naturally to the study of Suzuki and Kubo for the dynamical susceptibility of magnetic system in the Ising spin limit. As an illustrative example, the application of the present theory to an electric dipolar system with the polyorientational ordering and disordering is also given.

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A classical quasiparticle formulation is developed to describe the transport properties of a gas of independent classical electrons which interact via a finite range potential with a fixed random array of impurity ions. Calculations are carried out to terms of order λ⁴, where λ is the strength of the interaction potential. It is shown that both the electron velocity and the interaction potential are renormalised in the quasiparticle description.

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A mean field theoretical mode is presented to show that a first order transition from semimetallic to semiconducting distributions of carriers can result from the Landau quantization by a strong magnetic field applied to a semimetal. The possibility of the excitonic transition is ignored by assuming that intraband (electron-electron and hole-hole) exchanges dominate the interband exchange. The phase diagram including critical point and limits of supercooling and superheating is obtained. The enhancement of the sound attenuation by the critical fluctuation is also discussed.

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Precise measurement of the specific heat of two-dimensional Ising-like antiferromagnets K₂CoF₄ and Rb₂CoF₄ near the transition temperature are reported. A symmetric logarithmic singularity is observed at the transition temperature in both materials. The result is in excellent agreement with Onsager’s solution for the two-dimensional Ising model. Further, to clarify the short-range order effect in the two-dimensional Ising-like system, temperature variation of magnetic specific heat of K₂CoF₄ is also examined over a wide temperature range.

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A self trapped antiferromagnetic polaron at finite temperatures is studied in detail in the region where the band width E₀ is larger than the s–f exchange energy IS. Fluctuation effect is taken into account to the order of (IS⁄E₀)². Within this approximation, the extended molecular field theory is applicable for the localized spins. A large magnetic polaron can exist in which the localized spins are aligned nearly ferromagnetically. With increasing temperature, the fluctuation effect reduces the effective field on the localized spins, making the effective radius of the polaron larger and the polaron itself unstable. The overall feature of the magnetic polaron in the narrow band limit is also investigated on the simplified model.

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Well above the threshold for acoustoelectric instability, the time-dependent Ginzburg-Landau equation governing the motion of a phonon system in the threshold region breaks down on account of the parametric generation of subharmonic phonons, and in some cases it gives rise to an undamped oscillatory behavior of the system. It is suggested that the tremendous fluctuation in the acoustoelectric current is a manifestation to this behavior.

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The relaxed excited state of the F-center in alkali halides is studied theoretically as a vibronic system consisting of 2s and 2p electronic states interacting with local mode phonons. The model Hamiltonian is introduced which contains the s-, p- and d-like interaction modes. The vibronic problem for the s- and p-modes is solved numerically in the case of intermediate coupling strength and the energy schemes thus obtained are presented.

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Various experiments on the relaxed excited state of the F-center are analyzed in the framework of the vibronic model which consists of the 2s and 2p electronic states interacting with the s- and p-like local mode phonons. By comparing the theoretical calculations based on the exact solutions of the vibronic Hamiltonian with observed values of various quantities, the values of three parameters: 2s-2p energy difference Δ with phonon energy as the unit, the s- and p-mode coupling constants S₀ and S₁, are determined consistently. The best fit values for KCl are Δ\simeq1.25, S₀\simeq1.0, S₁\simeq1.5. The red Stark shift of the emission band can be explained by taking into account the interference of the adiabatic potential energy surfaces of the 2s and 2p states caused by the s-mode interaction.

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The concept of “subspecies” is introduced as convenient for investigating transition between isogenous ferroic phases (i.e., ferroic phases derived from a common prototype) and some other subjects. Examples of isogenous ferroic phases belonging to the same species and different subspecies are presented and discussed. All the species each divisible into more than one subspecies and all these subspecies are determined and tabulated.

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A voltage switching effect in current-biased imperfect tunnel junctions has been investigated experimentally and a model based on self-heating in the microshorts is employed to explain the observed voltage snapback.

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The resistive state of the current-carrying type 2 superconducting rod in a longitudinal magnetic field was studied for Pb–Tl alloys. The herical structure composed of two kinds of domains was found from the measurement of the potential distribution on the sample surface. The larger domain was confirmed directly to be in a flux flow state and the other domain was estimated to be in a normal state by some theoretical considerations. The direction of the boundary between these domains was dependent only on the direction of magnetic field at the surface.

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Low temperature specific heat and electrical resistivity of isoelectronic CrMo alloys containing up to 36.6 atomic % Mo were measured in order to study spin density wave (SDW) magnetism. Linear specific heat coefficient increases with Mo concentration and goes through a maximum, where SDW vanishes. The relation between linear specific heat coefficient and Néel temperature is discussed in reference to a recent spin fluctuation theory introduced into itinerant antiferromagnetism.

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The normal and the superconducting states of a single crystal V₃Si were studied by the usual pulse-echo method of ultrasonics at about 100 MHz. The magnetic field dependence of the ultrasonic attenuation slightly below T_c showed a complicated behavior characterized by four critical fields, which indicated the mixture of cubic and tetragonal phases. It was found that the critical temperature in the tetragonal phase T_c(Tet.) should be a little bit (∼0.1 K) lower than that in the cubic phase T_c(Cub.). It was also found that both the second critical fields H_c2(Cub.) and H_c2(Tet.) showed a linear ΔT (≡T_c−T)-dependence in the same way as those of usual type-II superconductors. The ratio of the H_c2(Tet.) to the H_c2(Cub.) was about 0.84, which may correspond to the ratio of the Fermi velocity in the cubic phase to that in the tetragonal phase. From the temperature dependence of the critical attenuations Δα, the values of the ultrasonic attenuation at each critical field, we obtained a formula as Δα(Tet.)∝(ΔT)^2⁄3.

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The antiferromagnetic structure found in FeI₂ is investigated theoretically. In order to explain the ordered spin structure, the intraplane exchange interactions in a hexagonal layer J₁, J₂ and J₃, and the interplane exchange interactions J₁′, J₂′ between adjacent layers and J₁″ between second nearest layers have been taken into account, and the following conditions among them are derived; J₂<0, J₂−2J₃>0, J₁−2J₂<0, J₁″<0 and 2|J₁″|>|J₁′−2J₂′|. It is pointed out that the ground states are quadruply degenerate including the FeI₂-structure and the degeneracy cannot be removed by any magnetic interactions. Discussion on this degeneracy and comparison with experiments to estimate the exchange constants are also made.

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The forced magnetostriction constants of the ferromagnetic alloys Au₄Mn, Cu₂Mn_1.2In_0.8 and MnSb were measured up to a magnetic field intensity of about 20 kOe over a temperature range from liquid air temperature to room temperature. By means of thermodynamical relations, the pressure coefficient of the absolute saturation magnetization 1⁄σ₀·(dσ₀⁄dp) was found to be −3.7×10⁻¹¹ (cm²/dyne) for Au₄Mn, −0.055×10⁻¹¹ (cm²/dyne) for Cu₂Mn_1.2In_0.8 and −0.59×10⁻¹¹ (cm²/dyne) for MnSb, respectively. From these results and a relation based on the molecular field theory, the pressure coefficients of the exchange interaction 1⁄J·(dJ⁄dp) are estimated to be 8.2×10⁻¹¹ (cm²/dyne) for Au₄Mn, 0.44×10⁻¹¹ (cm²/dyne) for Cu₂Mn_1.2In_0.8 and 0.60×10⁻¹¹ (cm²/dyne) for MnSb, respectively. The dependence of the exchange interaction on lattice constant is discussed.

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The ⁵⁹Co NMR has been observed in the ordered and disordered Fe–Co alloys with 48, 50 and 52 at % Co. Analysing the positions of satellite lines, the effect of first, second and third nearest neighbor atoms on the hyperfine field at a Co nucleus is discussed in terms of an empirical equation, H_Co=aμ_co+b₁Σμ_1n+b₂Σμ_2n+b₃Σμ_3n. Using the estimated values of the parameters a, b₁, b₂ and b₃, the spectra of Fe₅₀Co₅₀ alloys with various ordering parameters were calculated and found to be in good agreement with the observed spectra.

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It has been well know that the typical paramagnetic compound manganese Tutton salt shows an antiferromagnetism with a canted weak ferromagnetism below T_N=0.175 K. Recent experiments in the temperature region of millidegree have revealed further that another transformation into the other antiferromagnetic state with hidden canting occurs at about 70 mK. A quantitative explanation of this spin reorientation phenomenon is undertaken based on the four-sublattice model. The free energies for the two possible spin structures are calculated by the molecular field approximation from the Hamiltonian which consists of the magnetic dipole interaction, the exchange interaction and the crystalline field potential. It is shown that the spin reorientation can occur for reasonable values of the exchange parameters and for either signs of D. With the use of the exchange parameters which can explain the spin reorientation, the temperature dependences of the sublattice magnetization and the magnetic susceptibilities are calculated.

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The Mn⁵⁵ NMR in MnAs has been observed as a function of pressure up to 7 kbar at 77 K. The NMR is observed at 235 MHz in the hexagonal phase below about 4 kbar, while it is observed between 140 and 175 MHz in the orthorhombic phase above about 4 kbar. In the orthorhombic phase the NMR result is interpreted on the basis of a double spiral spin structure, and the magnetic moment estimated from the hyperfine field suggests a low-spin configulation of Mn atom.

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NMR of Co⁵⁹ has been performed in ferromagnetic PdCo alloys. The internal field changes from −215 kOe in pure Co metal to 230±5 kOe in alloys of Co diluted in Pd. The results are consistent with the previous measurements by nuclear polarization and Mössbauer effect experiments. The line width is very broad in alloys with low Co concentration. Even in 0.5% Co alloy, the width still has the value of 50 MHz. T₂ shows rapid decrease with decreasing Co concentration. The experiment has also been performed on Co⁵⁹ in ferromagnetic Pd_xNi_1−xCo system. The results are quite similar to those in PdCo alloys.

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A measurement has been made of the spontaneous Hall coefficient R_s in the Fe–Ni alloys containing 34.5∼42 at % Ni over the temperature range from 77 K to the Curie temperatures. In the 34.5∼40 at % Ni alloys, R_s is proportional to T² at low temperatures and changes to T^1.0∼1.4 dependences with increasing temperature. In the 42 at % Ni R_s varies with T⁴ in low temperature regions and with T² above 400 K. The temperature variations of R_s in Invar alloys can be interpreted by the Kagan and Maksimov theory based on the mixed spin-orbit coupling between localized d electrons and conductive s electrons, while itinerant magnetic electron models are rather applicable to that of R_s in the 42 at % Ni.

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The investigation in the previous paper on the collective motion of an electron-hole system in a magnetic field is extended to the cases where the constant energy surfaces are ellipsoidal and some of them are tilted away from the direction of applied magnetic field. The results are applied to Bi and the dispersion relations and the polarization properties of the charge-density waves are discussed.

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An ab initio calculation carried out to investigate the electronic structure of an impurity atom of non-transition element in Cu. The present calculation leads to the initial increase of the coefficient of the linear term in the capacity, γ, of Cu-based alloy with addition of polyvalent non-transition elements. The observed soft X-ray K_β emission spectra for impurities of Al and Si in Cu, Ni and Fe can be explained by using the calculated local density of states with p symmetry at the impurity site. A brief discussion is also given for the L_2,3 emission spectra. The Knight shift and T₁ of NMR of an impurity atom in Cu are calculated and compared with experimental results.

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The paramagnetic resonance has been measured on Mn ions (0.02–2.2 at%) in p-type SnTe crystals with carrier density 1.2−2×10²⁰ cm⁻³, and partly in n-type PbTe crystals, over the temperature range 120–480 K. For low Mn contents the hyperfine interaction constants A were found to be 56.0±0.2×10⁻⁴ cm⁻¹ for SnTe and 61.0±0.2×10⁻⁴ cm⁻¹ for PbTe, and the Debye temperatures θ were estimated from their temperature dependence; θ=200 K for SnTe and 110 K for PbTe. It was found that the g-values of SnTe (approximately g=2) were almost independent of temperature and Mn content. Finally, the susceptibility data of SnTe with 0.88 and 2.2 at% Mn are presented to show some possibility of magnetic inclusions in the grown crystal.

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The pressure dependence of NMR shift of F¹⁹ in a single crystal of KNiF₃ has been measured under hydrostatic pressure up to 8 kbar at room temperature. The volume derivatives of the isotropic hyperfine interaction A_s and the anisotropic one A_σ are obtained as functions of that of the spin expectation value ⟨S_z⟩ of Ni²⁺ ion. The volume derivative of −⟨S_z⟩ can be calculated from the pressure dependence data of the Néel temperature using the high-temperature-series-expansion method as dln (−⟨S_z⟩)⁄dln V=5.4. Using this value, the volume derivatives of admixture and covalency parameters λ_s, λ_σ, γ_s, γ_σ are given as follows, respectively: dln λ_s⁄dln V=−2.2, dln λ_σ⁄dln V=−2.3, dln γ_s⁄dln V=−4.9 and dln γ_σ⁄dln V=−2.9. Brief discussions are given on the pressure dependence of the covalency parameters and the superexchange interaction J.

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The magnetoresistance (MR) in epitaxial SnTe at 77 K depends sensitively on nominal carrier (hole) density p^*. Results at p^*=3.7×10¹⁹ cm⁻³ are explained by the simple ⟨111⟩ prolate ellipsoidal model with the value of 6.2 for the effective mass ratio of longitudinal to transverse. The combined model of the ⟨111⟩ and ⟨100⟩ ellipsoids is necessary for 3.7×10¹⁹ cm⁻³<p^*<2.5×10²⁰ cm⁻³. At p^*>2.5×10²⁰ cm⁻³, it seems to be impossible to account for the MR by the combined model of the ⟨111⟩, ⟨100⟩ and ⟨110⟩ ellipsoids. For the samples with lower p^* (p^*<4.5×10¹⁹ cm ⁻³), mobility μ_H decreases with decreasing p^*, contrary to the normal relation p^*μ_H=const. found for the samples with higher p^*. The MR seems to be affected by this anomaly.

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The dielectric constant and the spontaneous polarization of Ca₂Sr(C₂H₅CO₂)₆ have been measured for unannealed crystals and for crystals annealed at various temperatures between 150°C and 390°C. Almost all the unannealed crystals contain the internal bias field of about a few kilovolt per centimeter. For annealing temperatures higher than 330°C, the internal bias field vanishes completely and the Curie temperature T_c shifts remarkably toward lower temperatures. Deviations from the Curie-Weiss law are observed for dipolar dielectric constant ε−ε_∞ near T_c. It is found that ΔT=T_o−T_c, where T_o is the extrapolated Curie-Weiss temperature, increases with decreasing T_c.

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A phenomenological theory is presented for a possible isomorphous phase transition in polar crystals. The elastic Gibbs function G is expanded in a power series of a deviation of the polarization P from a fixed value P₀ as; G=G₀+a₀(T−T₀−Kp)ΔP+b₀(p−p₀)(ΔP)²+c(ΔP)³+d(ΔP)⁴, where T and p are temperature and hydrostatic pressure, respectively, and ΔP≡P−P₀. A first order isomorphous phase transition takes place at pressures less than a critical value of p_crit=p₀+3c²⁄(8b₀d), and above the critical pressure no phase transition exists. The critical behavior of the order parameter, dielectric constant, and specific heat is discussed. By choosing proper values of parameters, a qualitative agreement is obtained betweent the calculated and the observed pressure and temperature dependence of low frequency dielectric constant of Ca₂Pb(C₂H₅COO)₆ in the vicinity of the critical point.

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The Hall coefficient, R_H, of single crystal and single Q state of pure Cr was measured as a function of temperature between 360 and 4.2 K in fields up to 42 kG. From T_N(=311 K) to 150 K, R_H showed a hump similar to the electrical resistivity and it was explained by four band model in terms of carrier reduction by the nesting of Fermi surface of the electron and the hole octahedron due to the antiferromagnetic state. In the temperature between 50 and 30 K, minima of R_H were observed and it was considered arising from freezing out of Umklapp process in electron-phonon scattering. Below 30 K, a rapid increase of R_H with decreasing temperature was observed in lower field. This result was explained by an excitation across the second order energy gap arising from the effect of the nesting. The gap was estimated to be 7.6±0.8 meV.

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For studying the electron scattering by acoustic phonons and stacking faults, the electrical resistivity of graphite is calculated. Main results of the present calculation are as follows: The acoustic phonon scattering gives rise to the ratio of resistivity ρ_c⁄ρ_a∼10², where ρ_c indicates the c-axis resistivity and ρ_a the basal plane resistivity. ρ_c increases monotonically with the concentration of stacking faults, while ρ_a is independent of it. The stacking fault associated with the basal dislocation ribbon gives the most effective electron scattering among various types of faults. The ratio ρ_c⁄ρ_a becomes 10⁴ at room temperature when the mean distance between the stacking faults is assumed to be 200Å.

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The copper-decoration pattern of dislocations in silicon single crystal was studied by X-ray diffraction topography (Lang’s method). Linear images of single or double line were observed on a decorated 90° (pure edge) dislocation. A “stem-and-leaves” pattern as reported by earlier workers without direct determination of the type of dislocation was observed on a 60° dislocation, similar to a 0° (pure screw) dislocation. Similar results were obtained in the case of curved dislocations. The type of a dislocation was thus revealed to influence on the decoration pattern more definitely than so far considered.

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The effect of uniaxial stress and the Zeeman effect on spectra ⁴A₂→²E(²D) are investigated at 4.2 K by using applied uniaxial stress P up to 2.4 kbar and applied magnetic field up to 79 kOe. (i) The lowest two excited vibronic states have the same g_⁄⁄-values with each other: +0.54 for Cs₃CoCl₅ and +0.73 for Cs₃CoBr₅. (ii) The energy difference between the above two states of Cs₃CoCl₅ decreases, while that of Cs₃CoBr₅ increases, with the increase of |P| in P⊥(001). (iii) Intensities of some absorption-lines of Cs₃CoCl₅ changed drastically with P in P⊥(001). It is shown that these three experimental facts are typical results brought about by the Jahn-Teller coupling with the ν₂-mode. From these, parameters E_JT⁄hν₂=1.1∼1.6 [0.5∼1.0] and 2Δ₀⁄hν₂=1.3∼1.7 [2.4∼2.8] are obtained for Cs₃CoCl₅[Cs₃CoBr₅], where E_JT is the Jahn-Teller stabilization energy, and 2Δ₀ is the splitting of ²E(²D) in E_JT=0 and P=0

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The boundary of a magnetized plasma surrounded by a neutral gas is discussed theoretically by the continuum approach based on the assumption of constant but unequal temperatures. The condition under which a steady state solution exists, the thickness of the boundary, the diffusion flux and the profiles of pressure and magnetic field are calculated. A large pressure gradient may be induced in the boundary due to the effect of diamagnetism of the ambipolar diffusion.

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A pulsed nuclear quadrupole resonance (NQR) spectrometer was constructed and with it the temperature dependences of relaxation of N¹⁴ nucleus in ethylenediamine have been studied between 63 K and 274 K. As the temperature rises, two measured relaxation times, T_1s amd T_1l which characterize the nuclear relaxation of the nitrogen NQR lines, approach gradually each other above 200 K. The obtained results show that the dominant relaxation mechanism below 140 K is attributed to the thermal torsional motion and that above 150 K is a molecular motion activated over the potential barrier of about 6 kcal/mol. A type of twisting motion of amino groups between two equivalent staggered cis positions is suggestive for the molecular motion.

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Experimental studies are presented of the wave characteristics and associated plasma heating in a system composed of two counterstreaming electron beams and a longitudinally magnetized inhomogeneous plasma. Such an injection of two beams makes the plasma potential strongly negative, and produces the cross-field current. Three types of electrostatic instabilities are excited by the cross-field current, i.e., lower-hybrid instability, ion-cyclotron harmonic instability, and modified ion-cyclotron instability. As the latter two instabilities grow strongly, nonlinear wave mixing develops between them. Corresponding to the rapid growth of these instabilities, substantial ion and electron heating takes place in the direction perpendicular and parallel to the magnetic field, respectively. Heating mechanism of ions is also discussed, and it is found that the energetic ion production is attributed to the lower-hybrid turbulent heating.

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A longitudinal electron plasma oscillation having a narrow spectral width was spontaneously excited in a beam plasma system. As the frequency of the beam modulation approaches that of the spontaneous electron plasma oscillation, we observed that the electron plasma oscillation suffered catastropic suppression, while the oscillation with the same frequency as the modulation one was enhanced suddenly. Asymmetry and hysteresis of oscillation amplitude were observed. These nonlinear phenomena are well explained by an equation of the van der Pol type including a driving term and a cubic nonlinear term. The magnitude of the nonlinear term was estimated.

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The effect of a high frequency field on a flute like mode is investigated. The experiment has been made on a plasma produced by means of the molecular ion injection into a simple mirror. The flute like mode arises from the plasma rotation due to a static electric field, which is controlable by means of potential applied to the end plates. The strength of the high frequency field increases with radius and the frequency is near to the ion cyclotron frequency. It is confirmed from the relation between the hf field strength needed to suppress the wave and the plasma potential giving a rise in the wave that the hf electric field parallel to a confining steady state magnetic field reveals major effect on the suppression of the flute like mode and that the perpendicular one has minor effect.

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An analysis of the motion of collisional plasma cylinder in radial electric and axial magnetic fields is presented. The Bolzmann equation for the plasma motion is expressed in components of cylindrical coordinates. After some simplification of the problem, the Boltzmann equation is reduced to a set of equations of 4th order in V_r or V_θ by a proper and simple assumption. It is concluded that, from the results of numerical computation, the cylindrical effect decreases the effective frictional force acting on the rotating plasma, which is caused by collisions of plasma particles with neutrals.

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Accurate bounds for the effective diffusion constant and for the permeability (Darcy’s constant) of the porous media are obtained by a new variational formulation. These bounds are expressed in terms of the three two-point correlation functions, surface-surface, surface-void and void-void correlations. The results are applied to a randomly imbedded sphere model, and are found to agree well with the previous bound expressed by the three-point correlation functions.

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In application of the reductive perturbation method to certain systems such as passive (or active) systems, mass conservation is violated sometimes. It is sown by an exactly solvable example that this difficulty originates in the following fact: the conservation law involves the integral over the whole space, while for passive (or active) systems the reductive perturbation method is not valid over the whole space.

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The spectrum intensity of the current of nonlinear resonance circuit driven by random and periodic voltages is investigated by solving two dimensional Langevin equations approximately, and the occurrence of a large current fluctuation is expected in a certain range of frequency. This phenomenon is also verified experimentally by observing the current noise in a nonlinear resonance circuit, which is composed of an ordinary inductance and a nonlinear capacitor made from ferroelectric tri-glycine sulphate.

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Shower size vs average shower age and characteristic length of local high energy event vs shower size showed some change in slope around size of (5−10)×10⁶ in extensive air shower. This tendency indicates some characteristics in interaction scheme around 10¹⁷ eV of primary energy.

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The specific heats of CoCl₂·6H₂O, CoBr₂·6H₂O and NiCl₂·6H₂O are measured in spin wave region. The results are not in agreement with the theoretical calculation of the modified spin wave theory of Eisle and Keffer, using spin wave gap energy obtained from AFMR measurements, for all substances. Especially, in the case of CoCl₂·6H₂O, the qualitative disagreement is found.

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The NMR of copper nuclei in CsCuCl₃ has been studied at 1.77 K. NMR lines of Cu⁶³ nuclei were observed at 169.2 MHz with two satellite lines equally split by the quadrupole interaction. The analyses of the hyperfine field and the quadrupole splitting give that the spin direction of the Cu²⁺ ions is parallel to the local z-axis. Since the local z-axes have a helical nature along the c-axis, a screw spin arrangement at the ordered state is verified from the NMR results.

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Disordered hexagonal close packed ζ phase. Ag–Al, was studied by X-ray and electron diffraction methods. Diffuse scattering due to short range order was observed. The diffuse intensity distribution is characterized by its peculiar shape and the shift of the maximum position with the change of the Al concentration. The features resemble those of fcc disordered alloys such as Cu₃Au and αCu–Al where the Fermi surfaces are reflected in the diffuse scattering of X-rays.

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The ferroelasticity of rare earth pentaphosphates, ReP₅O₁₄ (Re : La, Ce, Pr, Nd, Sm, Eu, Gd and Tb) which belongs to the species mmmF2/m is studied by DSC, Weissenberg camera and polarizing microscope. Anomaly of heat capacity at the ferroelastic transition point (second order), ferroelastic hysteresis loop, space group in para phase (Pncm a=8.822, b=9.142, c=13.13A at 150°C LaP₅O₁₄), temperature dependence of ferroelastic order parameter and indicatrix are obtained.

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No anomaly was detected within the experimental error of ±0.2% in the heat capacity of solid HCl, either single crystal or polycrystals, that corresponds to the transition at 120 K proposed by neutron diffraction studies.

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Dielectric constant of ferroelectric triglycine selenate was measured at hydrostatic pressures around 5 kbar in the vicinity of the Curie temperature. A discontinuous charge of the dielectric constant at the Curie temperature and a thermal hysteresis of the transition (typically about 0.2°C at 5.28 kbar) were found. The result indicates that the order of the ferroelectric transition changes from second to first order by application of hydrostatic pressure. Unusual dielectric properties of TGSe at high pressures so far reported can be interpreted on the basis of the order-change in the transition.

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