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LiNbO3:Mg crystals doped with 0–8 mol. % Mg with stoichiometric, intermediate and congruent compositions were systematically investigated by Raman spectroscopy in backscattering y(zx)y, y(zz)y and z(xx)z geometries. The damping was found to be a very sensitive parameter for the characterization of the crystal composition. The half-widths of E(TO3)– E(TO9) and A 1(TO1)– A 1(TO4) bands having significant composition dependence for the undoped LiNbO3 crystals show only a weak Mg concentration dependence below the photorefractive threshold, which is a consequence of the counteracting effect of the decreasing NbLi and increasing MgLi contents. The half-widths of the bands, however, increase linearly with growing Mg content for samples above the threshold, irrespective of the Li/Nb ratio. The change in the Mg concentration dependence at a given Li/Nb ratio determines the same threshold value as that concluded from IR and UV spectroscopic measurements. The half-width of the main A 1(LO4) band at 873 cm-1 increases linearly with growing Mg concentration, but no threshold effect is observed. However, the ratio of the area of the main band and the high-frequency sideband shows a threshold effect that can be interpreted by the existing defect incorporation models. The small Raman band at about 740 cm-1 attributed earlier to NbLi vibration is also detected in above-threshold LiNbO3:Mg crystals, which can be explained by the vibration of Nb ions in Mg4Nb2O9 defect clusters appearing at high Mg concentrations. [ABSTRACT FROM AUTHOR]

Abstract: The EPR g factors of the trigonal Ti3+ center A in LiF:Ti3+ and two additional trigonal Ti3+ centers B and C in LiF:Ti3+:Mg2+ crystals are calculated from the third-order perturbation formulas based on the cluster approach. From the calculations and by considering the Ti3+ displacement along 〈111〉 axis obtained by ENDOR experiment, the defect models for the three Ti3+ centers are suggested. For center A, there are two possible models: (i) [Ti3+F3 −O3 2−] cluster and (ii) [Ti3+F6 −] cluster with the Ti3+ off-center caused by a neighboring Li+ vacancy () at 〈111〉 axis. The latter seems the more likely. The defect models of centers B and C are the [Ti3+F3 −O3 2−] clusters associated with a neighboring: Mg2+ ion at the Li+ site along 〈111〉 axis in the vicinity of three F− ions and three O2− ions, respectively. The reasonableness of these models is discussed. [Copyright &y& Elsevier]

The structure and harmonic vibrations of MgnOn (n = 3–10) clusters have been investigated using density functional theory. All structures are found to be cumulenic Dnh rings (equal bonds, alternating angles), with one intense out-of-plane mode and three infrared (IR)-active degenerate modes, of which the highest one is extremely intense and increases asymptotically to 1000 cm-1 for n = 10 at the B3LYP/6-311++G(2d,2p) level. Comparisons with C2n clusters show that BnNn and BenOn clusters, the structure and bonding type for the MgnOn clusters are consistent with those of the C2n (n = 3, 5, 7,...) clusters BnNn(n = 3–10) and BenOn(n = 3–10) clusters. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [ABSTRACT FROM AUTHOR]

Abstract: We describe the ultraviolet-light one-color photorefraction (UV-OPR) at 351nm in LiNbO3 crystals with different Mg-doping concentrations and [Li]/[Nb] ratios. It is shown that as the Mg-doping concentration and/or the [Li]/[Nb] ratio increase, the refractive index change and the two-beam coupling gain increase but the response time decreases. It is also shown that the recording sensitivity as large as ∼27cm/J is obtainable at a recording intensity of ∼1W/cm2 in near-stoichiometric LiNbO3 doped with 2mol% Mg. This sensitivity is approximately one order of magnitude higher than those for other LiNbO3 crystals. We also describe the ultraviolet-light-gating two-color photorefraction (UV-TPR) using 365nm gating and 633nm recording beams in LiNbO3 crystals with different Mg-doping concentrations and [Li]/[Nb] ratios. It is shown that UV-TPR is only observed in near-stoichiometric crystals and the grating-formation dynamics strongly depend on the Mg concentration. [Copyright &y& Elsevier]

Abstract: Several near-stoichiometric lithium niobate crystals with the doping concentration of Mg near the second threshold were prepared by vapor transport equilibrium technique. All these samples show no laser beam distortion under a light intensity of 26MW/cm2, that is three orders of magnitude higher than that of 5mol% Mg doped congruent LiNbO3. And the light-induced refractive index (Δn) in one of them is as small as 4.6×10−7, which is two orders of magnitude lower than that of congruent crystals. [Copyright &y& Elsevier]

The quantitative phase-mapping of the domain nucleation in MgO:LiNbO3crystals is presented by using the digital holographic interferometry. An unexpected peak phase at the beginning of the domain nucleation is observed and it is lowered as the spreading of the domain nucleus. The existence of the nucleus changes the moving speed of the domain wall by pinning it for 3 s. Such in-situquantitative analysis of the domain nucleation process is a key to optimizing domain structure fabrication. [ABSTRACT FROM AUTHOR]

We present a temperature-dependent Sellmeier equation for the extraordinary refractive index of 5 mol % MgO doped congruent lithium niobate. This equation is adapted for wavelengths in the range of 1.3–5 μm and temperatures between 40 °C and 200 °C. The calculation of the appropriate Sellmeier coefficients is based on the wavelengths of the signal and idler radiation measured for quasi-phase-matched optical parametric generators excited by 10-ns-long, 1064-nm pulses of a Q-switched Nd:YVO4 laser. [ABSTRACT FROM AUTHOR]

We present a temperature-dependent Sellmeier equation for the extraordinary refractive index of 5 mol % MgO doped congruent lithium niobate. This equation is adapted for wavelengths in the range of 1.3–5 μm and temperatures between 40 °C and 200 °C. The calculation of the appropriate Sellmeier coefficients is based on the wavelengths of the signal and idler radiation measured for quasi-phase-matched optical parametric generators excited by 10-ns-long, 1064-nm pulses of a Q-switched Nd:YVO4 laser. [ABSTRACT FROM AUTHOR]

The six-dimensional (6D) low density elimination method (LDEM) has been applied to solve the p-type icosahedral Zn 75 Mg 16 Ho 9 quasicrystal. The reconstructed electron density distribution by the LDEM exhibits three large occupation domains (ODs) centred at (0,?0,?0,?0,?0,?0), (,?,?,?,?,?), and (,?0,?0,?0,?0,?0) in the 6D primitive unit cell, and the OD at (,?,?,?,?,?) contains Ho atoms, which mainly distribute around the threefold directions. A geometrical analysis confirms that a rhombic triacontahedron cluster which includes a Bergman-type cluster is a basic building unit of the structure. [ABSTRACT FROM AUTHOR]

The corrosion behaviour of three low index planes of an hcp magnesium (Mg) single crystal was investigated in 10-2M NaCl/10-4M dichromate solution. The Mg (0001) surface exhibited pitting corrosion susceptibility at the open circuit potential. However, the (1010), and (1120) surfaces were passive at open circuit and pitting only initiated at potentials slightly anodic to their open circuit potentials. The onset of stable dissolution in the three surfaces was marked by the formation and propagation of corrosion filaments. For the three surfaces investigated, pit shape was non-geometric, however, pit propagation was generally found to occur along preferential crystallographic directions. An analysis of the preferred crystallographic directions is presented. [ABSTRACT FROM AUTHOR]

The dynamic response of a homogeneous, Isotropic, generalized thermoelastic half-space with voids subjected to normal, tangential force and thermal source is investigated. The displacements, stresses, temperature distribution, and change in volume fraction field so obtained in the physical domain are computed numerically and illustrated graphically. The numerical results of these quantities for magnesium crystal-tike material are illustrated to depict the response of various sources in the Lord-Shulman and Green-Lindsay theories for an insulated boundary and temperature gradient boundary. [ABSTRACT FROM AUTHOR]

The crystallization process of MgO-CaO-SiO2-Na2O glasses in the presence of CaF2 and MoO3 nucleating agents was investigated by DTA, XRD and SEM. The effect of compositional changes on bulk crystallization and growth morphology has been studied. After a two-stage heat treatment, the phases such as wollastonite, diopside and cristobalite, were identified. The ability of CaF2 and MoO3 pair as nucleating agents in inducing bulk nucleation in these glasses was attributed to the surface tension and viscosity reductions. The observed pore formation phenomenon upon the increase of MgO content in these glass-ceramics was related to the difference in density between the residual glass and diopside as the main crystalline phase. [ABSTRACT FROM AUTHOR]

The structure of the pseudocubic Mg[sub 51]Zn[sub 20] phase, which is related to icosahedral quasicrystals, was interpreted as a modulated crystal. It basically comprises distorted close-packed layers with ordered atomic vacancies. The basic reciprocal-lattice vectors point to the vertices of a distorted icosahedron. A relationship in reciprocal space between the Mg[sub 51]Zn[sub 20] phase and the icosahedral Zn–Mg–Dy quasicrystal was also investigated. [ABSTRACT FROM AUTHOR]

We demonstrated an integratable passively Q-switched (PQS) Tm,Mg:LiNbO 3 laser with a single-walled carbon nanotube saturable absorber (SWCNT-SA) for the first time. Its laser characteristics were investigated with different output couplers. At the pump power of 9.5 W, the maximum output power of 0.93 W around 1963 nm was obtained with the output transmission of 1%. The optical conversion efficiency is 9.79%, corresponding to a slope efficiency of 17.4%. For pulsed operation, a shortest pulse width attained was 640 ns, with the pulse repetition frequency of 44.6 kHz, and the single pulse energy was 12.6 μJ. [ABSTRACT FROM AUTHOR]

Examines the magnesium whitlockite crystal deposition in articular cartilage from various joint sites. Description of specimens collected to determine magnesium whitlockite crystal deposition; Identification of the crystal deposition on the basis of morphology, size and elemental composition; Extent of deposition in human articular cartilage.

Based on a newly constructed Mg-Cu-Ni n-body potential, atomistic simulations revealed the underlying mechanism of metallic glass formation is the crystalline lattice collapsing while solute concentration exceeding a critical value, and predicted a quadrilateral region in the composition triangle, energetically favoring the formation of ternary Mg-Cu-Ni metallic glasses. Moreover, an optimized stoichiometry area around Mg60Cu17Ni23 was further located, at which the driving force for transforming the crystalline solid solution into a disordered state, i.e., the glassy phase reaches its maximum. Furthermore, by characterizing the local environments, the frustration of crystallization favorable short-range orders was revealed to be correlated with the optimum glass forming ability (GFA) in Mg-Cu-Ni system, interpreting the structural orgin of GFA and lending further support to the prediction results. [ABSTRACT FROM AUTHOR]

The formation of periodic structures and micro- and nanoparticles on the surface of polycrystalline magnesium under the action of a high-power proton-carbon ion beam of nanosecond duration have been studied. Spatial parameters of the observed structures and dimensions of particles are determined and possible mechanisms of their formation are considered. [ABSTRACT FROM AUTHOR]

Abstract: The destabilization of magnesium hydride (MgH2) by solid-state reaction with Si in a nanoscale under vacuum was studied. The nanostructured Si films were deposited on the nanocrystalline MgH2/Mg composite substrate by the pulsed laser deposition (PLD). The cross-sectional transmission electron microscopy (TEM) shows that the metastable Mg5Si6 is the only intermetallic compound formed in the Si–Mg region during the deposition. The destabilization of MgH2 by Si forming the Mg2Si intermetallic compound was not observed in a nanoscale at 150°C under vacuum. [Copyright &y& Elsevier]

The effect of MgO tunnel barriers on the magnetic moment of ultrathin magnetic Fe and Co layers is studied by polarized neutron reflectivity. The MgO barriers were grown by molecular beam epitaxy using either direct evaporation from a source crystal or evaporation of Mg in an oxygen background atmosphere. A decrease of the magnetic moment is observed for both Fe and Co, and atomic intermixing of 1.5–3.5 ML at interfaces between the Fe, Co, and MgO is determined. Evaporation from a MgO source crystal yields a tunnel layer which displays better stoichiometry and epitaxy than is obtained using the other growth method. [ABSTRACT FROM AUTHOR]

Here, the authors demonstrate a unique technique to form dense dislocations locally inside a single crystal with a rocksalt-type structure using femtosecond laser irradiation for the first time, to our knowledge. Cross-shaped patterns of micrometer size, originating from densely introduced dislocations, are formed around the focal point. The authors controlled three-dimensional propagation of dislocations by adjusting the pulse energy of femtosecond laser and numerical aperture of objective lens. [ABSTRACT FROM AUTHOR]

Here we describe the results of an atomic resolution study of the structure and composition of both the interior of the grains, and the grain boundaries in polycrystalline MgB[sub 2]. We find that there is no oxygen within the bulk of the grains but significant oxygen enrichment at the grain boundaries. The majority of grain boundaries contain BO[sub x] phases smaller than the coherence length, while others contain larger areas of MgO sandwiched between BO[sub x] layers. Such results naturally explain the differences in connectivity between the grains observed by other techniques. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents the experimental results on the 'spin-valve' system for magnetoresistive detection, based on epitaxial iron/palladium (Fe/Pd) bilayers grown on magnesium oxide (MgO) single crystals. Purpose of using the soft magnetic properties of epitaxial Fe/Pd bilayers; Role of Pd; Problems with giant magnetoresistance systems.

The crystal structure of the title compound, [Mg4Br2(CH3O)6(C4D8O)6], consists of discrete molecules with imposed symmetry Ci. The tetranuclear compound exhibits two crystallographically independent Mg atoms having distorted octahedral and trigonal-bipyramidal coordination spheres. The Mg atoms are bridged by two µ3-OMe and four µ2-OMe ligands, and their coordination is completed by two terminal Br and six tetrahydrofuran ligands. [ABSTRACT FROM AUTHOR]

Three Zn–Mg–Y alloys with nominal compositions of Zn 50 Mg 42 Y 8 and Zn 60 Mg 30 Y 10 were prepared by induction melting or gas atomisation. XRD and SEM analysis shows samples ZMY-1 and ZMY-2 consisted of multiple phases including icosahedral quasicrystal (QC) i-phase, hexagonal H-phase and Mg 7 Zn 3 , whilst ZMY-3 contained QC only. The hydrogen storage properties of the Zn–Mg–Y quasicrystal and ternary alloys were investigated for the first time. The quasicrystal sample ZMY-3 hydrogenated at 300 °C had 0.3 wt.% capacity and the DSC decomposition peak temperature was 503 °C. Amongst the three samples, the highest hydrogen storage capacity (0.9 wt.%) and the lowest decomposition peak temperature (445 °C) was achieved by sample ZMY-1. The pressure–composition–isotherm (PCI) curve of ZMY-1 sample showed a flat plateau gave a plateau pressure of 3.5 bar at 300 °C, which indicates a lower dehydrogenation enthalpy than MgH 2 . [ABSTRACT FROM AUTHOR]

The authors have completed their institutions to properly reflect the contributions of the affiliated institutions. [ABSTRACT FROM AUTHOR]

A correction to the article "Anisotropic Diffusion Behavior of Al in Mg: Diffusion Couple Study Using Mg Single Crystal" that was published in the 2013 issue is presented.

A graph is presented which describes the phase diagram of the Mg-Mn (Magnesium-Manganese) crystal.

Abstract: Mg0.4Al2.4O4 single crystals with good optical quality were successfully grown by the Czochralski method. The transmission spectrum indicated that the absorption edge of the crystal was at 220nm, while no apparent absorption peaks were found. The X-ray diffraction and DSC curve analysis showed that Mg0.4Al2.4O4 crystal was stable at room temperature. While after annealing in the air and hydrogen atmosphere at about 1200°C, Mg0.4Al2.4O4 decomposed into Al2O3 and (MgO)0.4(Al2O3) x (0.4< x <1.2). The reaction mainly occurred on the crystal surface, barely inside. [Copyright &y& Elsevier]