No abstract available

No abstract available

[en] We have performed a mechanical-spectroscopy study on hcp YH_x single crystals (x ≤ 0.1, vibrating-reed technique, 280 to 1750 Hz). In agreement with previous data from polycrystalline YH_x, we find an anelastic relaxation peak at ∼ 280 K. Our single crystals show a large anisotropy in the relaxation strength which demonstrates that this peak results from a Zener relaxation of hydrogen (H) pairs. Two types of H jumps determine the relaxation kinetics. Comparison with previous QNS data identifies the jumps that cause the relaxation, showing further that their jump rates follow, over ten orders of magnitude, an Arrhenius law with an activation energy of (0.60 ± 0.03) eV. (orig.)

[en] The boride is obtained by direct heating of elementary boron and the rare earth chloride

[en] Processing of bulk REBCO (RE = rare earth) superconductors for applications will be discussed. It would be attractive to operate devices at temperatures close to 77 K, the boiling point of cheap and abundant liquid nitrogen. Applications of REBCO superconductors in fault current limiters, flywheel batteries, trapped field magnets, hysteresis motors, levitation platforms etc. are in various stages of development at different centers. For realizing applications, the material has to be processed into near-net shape while simultaneously generating microstructures that support high current densities to high magnetic fields

No abstract available

[en] Solids containing boron icosahedra have structural elements common to many materials of current interest. For example, a B₆₀ shell with the same structure as C₆₀ is part of the structure of elemental boron. The boron-rich solids can thus provide insights into the structural properties of a variety of seemingly unrelated materials. Here scanning tunneling microscopy images of YB₆₆(100) are reported that reveal B₁₅₆ supericosahedra as discrete structural entities. While the structure of YB₆₆ is formally described in terms of such supericosahedra, this is the first evidence of their existence as stable units in their own right. copyright 1996 The American Physical Society

[en] Sesquicarbides of erbium, thulium and ytterbium having the structure of type Pu₂C₃, have been produced by synthesis from elements and by the thermobaric treatment under pressures of 30 to 90 kbars and at temperatures of 1200 deg to 1400 deg C. Using computer according to ''Roentgen 70'' programme, the coordinates of atoms in those and in earlier obtained sesquicarbides of yttrium and lutecium carbides have been specified

[en] Investigated is the alloy electron structure of Y-Si system using the X-ray diffraction analysis data and theoretical calculations. The conclusion has been made of application possibility of the model of overlapping zones to describe yttrium silicides electronic structure. States is the three-band zone structure for describing the yttrium silicides valency band

[en] Several yttrium-silicate composition with Y₂O₃ content within 44-56% have been synthesized. it is ascertained that employment of sol-gel technique permits preparation of luminescent materials on yttrium silicate basis, which compare favourably with bath-produced specimens. The influence of phase composition of sol-gel phosphors on basic performance indices: intensity and luminescence spectrum, has been analyzed