The Au−H (Gold-Hydrogen) system

Okamoto, H.; Massalski, T. B.

doi:10.1007/bf02880524

Cited by 107 publications

(164 citation statements)

References 5 publications

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“…Examination of the anisotropic atomic displacement parameters determined from neutron diffraction analysis shows that the Bi vibrations along the c-axis are enhanced with increasing temperature above the spin reorientation, suggesting a relationship with the welldocumented increase in magnetocrystalline anisotropy energy with temperature. Starting materials for the crystal growths were Bi shot (Cominco American, 99.9999%) and Mn pieces (Alfa Aesar, 99.95%), and the crystal were grown from a flux with excess Bi based on the published binary phase diagram [30]. The Mn pieces were lightly ground into a powder and 0.65 g of this material was then immediately combined with 35 g of Bi and loaded into an alumina crucible.…”

Section: Introductionmentioning

confidence: 99%

Symmetry-lowering lattice distortion at the spin reorientation in MnBi single crystals

et al. 2014

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Structural and physical properties determined by measurements on large single crystals of the anisotropic ferromagnet MnBi are reported. The findings support the importance of magnetoelastic effects in this material. X-ray diffraction reveals a structural phase transition at the spin reorientation temperature TSR = 90 K. The distortion is driven by magneto-elastic coupling, and upon cooling transforms the structure from hexagonal to orthorhombic. Heat capacity measurements show a thermal anomaly at the crystallographic transition, which is suppressed rapidly by applied magnetic fields. Effects on the transport and anisotropic magnetic properties of the single crystals are also presented. Increasing anisotropy of the atomic displacement parameters for Bi with increasing temperature above TSR is revealed by neutron diffraction measurements. It is likely that this is directly related to the anisotropic thermal expansion in MnBi, which plays a key role in the spin reorientation and magnetocrystalline anisotropy. The identification of the true ground state crystal structure reported here may be important for future experimental and theoretical studies of this permanent magnet material, which have to date been performed and interpreted using only the high temperature structure.

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Section: Introductionmentioning

confidence: 99%

Symmetry-lowering lattice distortion at the spin reorientation in MnBi single crystals

et al. 2014

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“…According to the Al-Be phase diagram [67], the concentration of Al solute atoms is expected to be much less than 60 ppm which leads to an activation volume V solute > 2 × 10 −26 m −3 much larger than expected. Although O atoms can also be present, their concentration is also presumably very low, ruling out the interaction of twinning dislocations with solute atoms as the controlling mechanism.…”

Section: Twinning Dislocation Interaction With Solute Atomsmentioning

confidence: 88%

In situ TEM study of twin boundary migration in sub-micron Be fibers

Mompiou

Legros

Ensslen³

et al. 2015

Acta Materialia

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Deformation twinning in hexagonal crystals is often considered as a way to palliate the lack of independent slip systems. This mechanism might be either exacerbated or shut down in small-scale crystals whose mechanical behavior can significantly deviate from bulk materials. Here, we show that sub-micron beryllium fibers initially free of dislocation and tensile tested in-situ in a transmission electron microscope (TEM) deform by a {1012} 1011 twin thickening. The propagation speed of the twin boundary seems to be entirely controlled by the nucleation of twinning dislocations directly from the surface. The shear produced is in agreement with the repeated lateral motion of twinning dislocations. We demonstrate that the activation volume (V) associated with the twin boundary propagation can be retrieved from the measure of the twin boundary speed as the stress decreases as in a classical relaxation mechanical test. The value of V ≈ 8.3 ± 3.3 × 10 −29 m 3 is comparable to the value expected from surface nucleation. This text is a revised version of the article published in Acta Materialia, 96 (2015) 57-65

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“…The mechanism for Si material to appear in the fibre is a chemical reaction between the Al core and silica cladding. Al has a melting temperature of 660.32°C, so it melts when fed into the heating zone and keeps its molten state until oxidized 32 . Also as an active reducer, Al reduces the surrounding silica and produces Si atoms and Al 2 O 3 molecules 33 .…”

Section: Resultsmentioning

confidence: 99%

“…Most importantly, Si is completely miscible with Al in the liquid state, but their solubility with Al 2 O 3 is comparatively low 32,34 . As more and more Al 2 O 3 is produced, the excessive Al 2 O 3 precipitates out of molten Al.…”

Section: Resultsmentioning

confidence: 99%

Crystalline silicon core fibres from aluminium core preforms

et al. 2015

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Traditional fibre-optic drawing involves a thermally mediated geometric scaling where both the fibre materials and their relative positions are identical to those found in the fibre preform. To date, all thermally drawn fibres are limited to the preform composition and geometry. Here, we fabricate a metre-long crystalline silicon-core, silica-cladded fibre from a preform that does not contain any elemental silicon. An aluminium rod is inserted into a macroscopic silica tube and then thermally drawn. The aluminium atoms initially in the core reduce the silica, to produce silicon atoms and aluminium oxide molecules. The silicon atoms diffuse into the core, forming a large phase-separated molten silicon domain that is drawn into the crystalline silicon core fibre. The ability to produce crystalline silicon core fibre out of inexpensive aluminium and silica could pave the way for a simple and scalable method of incorporating silicon-based electronics and photonics into fibres.

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The Au−H (Gold-Hydrogen) system

Cited by 107 publications

References 5 publications

Symmetry-lowering lattice distortion at the spin reorientation in MnBi single crystals

Symmetry-lowering lattice distortion at the spin reorientation in MnBi single crystals

In situ TEM study of twin boundary migration in sub-micron Be fibers

Crystalline silicon core fibres from aluminium core preforms

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