[en] Recent syntheses of rare earth (RE) ternary superconductors such as (RE)Mo₆X₈(X=S or Se) and (RE)Rh₄B₄ have provided the first opportunity to explore the interaction between magnetism and superconductivity in detail owing to their particular crystal structure. The regular sublattice of the rare-earth ions in these new ternary compounds undergoes a ferro- or antiferromagnetic phase transition in the superconducting state. If the transition is antiferromagnetic, the superconductivity is preserved so that true coexistence results. If it is ferromagnetic, on the other hand, the superconductivity eventually gives way to uniform ferromagnetism at low temperatures. However, recent theories predict several possible states of coexistence even in ferromagnetic superconductors. This article reviews aspects of these new phase transitions in ternary superconductors. (author)

[en] The magnetization of the reentrant superconductor (Ersub(0.6)Hosub(0.4))Rh₄B₄ has been measured near the lower critical temperature, Tsub(c2). The anomalous temperature dependence of the critical field just above Tsub(c2) is explained as a result of the interaction with the spontaneous magnetization. (Auth.)

[en] The MXS preprocessor has been designed to reduce the execution time of programs using isotopic cross-section data and to both reduce the execution time and improve the accuracy of shielding-factor interpolation in the SIMMER-II accident analysis program. MXS is a dual-purpose preprocessing code to: (1) mix isotopes into materials and (2) fit analytic functions to the shelf-shielding data. The program uses the isotope microscopic neutron cross-section data from the CCCC standard interface file ISOTXS and the isotope Bondarenko self-shielding data from the CCCC standard interface file BRKOXS to generate cross-section and self-shielding data for materials. The materials may be a mixture of several isotopes. The self-shielding data for the materials may be the actual shielding factors or a set of coefficients for functions representing the background dependence of the shielding factors. A set of additional data is given to describe the functions necessary to interpolate the shielding factors over temperature

[en] The linear analysis by the six-moment method proposed by Shirazian for calculating the heat flux in a steep temperature gradient plasma is extended to the second order. The heat flux is expressed in terms of a ratio (inverse of Knudsen number) L/Λ, L and Λ are the scale length of the temperature gradient and the mean free path. In the collisional and small temperature gradient limit, the second order heat flux is q=0.1416[1-(9/52)(1-Rsub(t)²)][2/(3-Rsub(t))][2/(1+Rsub(t))]sup(5/2)q sub(L), (Shirazian's first order result is 0.1416 [2/(3-Rsub(t))][2/(1+Rsub(t))]sup(5/2)q sub(L)), where q sub(L) is the exact result derived by Landshoff for the Lorentzian plasma and Rsub(t)=Tsub(c)/Tsub(h), where Tsub(h) and Tsub(c) are the temperatures of hot and cold walls. The discrepany between q and q sub(L) comes from the lack of number of moments and the assumed form of the electron velocity distribution function. A new trial distribution function including eight moments is proposed which may be more appropriate for the Lorentzian plasma. A criterion for the choice of good trial function is proposed and tested. (author)

[en] The Chevrel phase compound DyMo₆S₈ becomes superconducting at 2.05 K and is antiferromagnetic (AFM) T/sub M/ = 0.4 K. Experiments with an applied magnetic field have shown that the AFM state is gradually suppressed and a ferromagnetic component seems to be induced before H/sub c2/ (1200 0e) is reached. The present experiments have been performed at the small-angle scattering facility D11 at the Institut Laue Langevin with a dilution refrigerator and applied fields of up to 2000 0e. Neutron wavelengths of 6.25 and 10A have been used allowing a minimum wavevector Q/sub min/ approx. = 0.005 A^-1 to be achieved. For increasing H we find a sudden increase in the small-angle scattering at H = 180 0e, which we identify as H/sub c1/. With a position sensitive detector we have also investigated the scattering as a function of the relative orientation of Q Vector and H Vector. For a simple paramagnet we would expect more magnetic intensity with Q Vector perpendicular H Vector than with Q Vector parallel H Vector, however, we find the exact reverse with somewhat more intensity for Q Vector parallel H Vector. This is not understood, but we propose that the small-angle scattering is predominantly inelastic. Similar anisotropic effects have been found in other Chevrel phase systems. 7 references

[en] Magnetization measurements on the heavy rare earth molybdenum sulfides, (RE)sub(1.2)Mo₆S₈ (RE = Gd, Tb, Dy and Ho) were performed to clarify further the natures of their magnetic orders found in recent resistivity and ac susceptibility measurements below 1 K. The variations of their magnetic and superconducting transition temperatures along the series of the rare earth ions in the Periodic Table are interpreted by means of available theories. (author)

[en] The resistance and ac susceptibility measurements on Tbsub (1.2)Mo₆S₈, Dysub(1.2)Mo₆S₈ and Ersub(1.2)Mo₆S₈ revealed a magnetic ordering in their superconducting state at 0.9, 0.4 and 0.15 K, respectively. Some of the important features of the ordering in each compound are discussed with reference to their upper critical field curves. (author)

[en] Normal-state specific heat and superconducting transition temperature measurements were performed on pure polycrystalline Nb and isoelectronic bcc Zr/sub x/Nb/sub 1-2x/Mo/sub x/ alloys (x = 0.02, 0.05, and 0.10). Measured T/sub c/ γ and theta/sub D/ all decline nearly linearly from the pure Nb values with increasing x. The changes are 15, 10, and 6 percent, respectively, for x = 0.1. T/sub cH/ calculated by Hopfield's theory, using data and linearly interpolated values of eta and theta/sub D//r√[theta²]/sub linear/, increases with x by 28 percent for x = 0.1. By relaxing the linear interpolation of theta/sub D//√[theta²], Hopfield's theory can be used to evaluate an average phonon frequency [theta²]/sub emp/ from data. It is found to be nearly constant at about 229⁰K, in contrast to√[theta²]/sub linear/, which declines by 8 percent at x = 0.1. We suggest that one possible explanation for this behavior is the dominance of incipient soft-phonon longitudinal modes which occur in Nb and presumably in the alloys. Miedema's method has been used to calculate the variation of both γ and T/sub c/ with alloying. The calculated γ is nearly constant, while the calculated T/sub c/ declines more quickly than the measured variation. The band-structure electron density of states calculated with the aid of McMillan's equation for these isoelectronic alloys is found to decline by 8 percent at x = 0.1, in contrast to the prediction of the rigid band model. Normal-state low-temperature specific heat measurements on a pure annealed polycrystalline sample of Nb yield γ = 7.80 +- 0.02 mJ mole^-1 K^-2 and theta/sub D/ = 276 +- 2 K, in excellent agreement with previous measurements. The break in slope of C/sub p/T vs. T² at 3.2 K is discussed. (6 figures, 1 table) (auth)

[en] A new science that treats three-dimensional phenomena in MHD generators is introduced. Parabolized Navier-Stokes equations are solved together with the kappa-epsilon two-equation turbulence model and with the electrodynamic equations. The rational Runge-Kutta method is used along the main flow direction and the Galerkin finite element method in the perpendicular cross section. It is shown that, even when the MHD interaction is still low, three-dimensional effects become clear near open- and short-loading conditions in the case of a diagonal-type generator, since a relatively large J(x) component is induced. 9 references

[en] An entirely new type of phase transition has been found in the superconducting compound Hosub(1.2)Mo₆S₈. The compound becomes superconducting at 1.2 K and returns to the normal state through the newly found, very sharp phase transition at 0.64 K. The latter transition is attributed to the magnetic ordering of the Ho³⁺ ions in the compound. (author)