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Short Range Order (short + range_order)
Selected AbstractsAtom Probe Tomography II.ADVANCED ENGINEERING MATERIALS, Issue 12 2006The Precipitation in Al Base Alloys Abstract This paper presents two illustrations of the study of phase separation in Al-based alloys by means of tomographic atom probe. In an AlMgSi alloy, calculations of pair correlation functions have revealed that the nature of solute short range order differs from a pre-aged specimen to a non-pre-aged specimen. This results in different responses to aged hardening treatments. Concerning Al3(Zr,Sc)-type dispersoids observed in another Al-based alloy, they are found to display a core-shell structure wherein Zr is mainly present in the dispersoids periphery. This duplex structure is likely to explain the relative stability of Al3(Zr,Sc) dispersoids. [source] Identification of Nucleation Center Sites in Thermally Annealed Hydrogenated Amorphous SiliconADVANCED FUNCTIONAL MATERIALS, Issue 14 2009A. Harv Mahan Abstract Utilizing the concepts of a critical crystallite size and local film inhomogeneity, it is shown that nucleation in thermally annealed hydrogenated amorphous silicon occurs in the more well ordered spatial regions in the network, which are defined by the initial inhomogeneous H distributions in the as-grown films. Although the film H evolves very early during annealing, the local film order is largely retained in the still amorphous films even after the vast majority of the H is evolved, and the more well ordered regions which are the nucleation center sites for crystallization are those spatial regions which do not initially contain clustered H, as probed by H NMR spectroscopy. The sizes of these better ordered regions relative to a critical crystallite size determine the film incubation times (the time before the onset of crystallization). Changes in film short range order upon H evolution, and the presence of microvoid type structures in the as grown films play no role in the crystallization process. While the creation of dangling bonds upon H evolution may play a role in the actual phase transformation itself, the film defect densities measured just prior to the onset of crystallization exhibit no trends which can be correlated with the film incubation times. [source] Determination of the local structure of the first and second shells in ordered and disordered Ni,Mn alloysJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001A. V. Ryazhkin The coordination numbers and the interatomic distances for 50, 75 and 80 at.% Ni-Mn alloys in ordered and disordered states are presented. A new method for determining the first and second nearest neighbor coordination numbers in a binary alloy is applied. It is shown that magnetic properties of these alloys depend on short range order in atomic arrangement. [source] Dependence of transport properties in tunnel junction on boron dopingPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010M. J. Shi Abstract Boron-doped hydrogenated silicon films with different gaseous doping ratio (B2H6/SiH4) were fabricated as recombination p layers in tunnel junctions. The measurements of I-V characteristics of the junctions and transparency spectra of p layer indicated that the best gaseous doping ratio of the recombination layer is 0.04, which is correlated to the degradation of short range order (SRO) in the inserted p thin film. The junction with such recombination layer has small resistance, near ohmic contact. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||