Lattice parameters of CO2-Kr cryoalloys

Abstract

Articles you may be interested inVoids and Mn-rich inclusions in a (Ga,Mn)As ferromagnetic semiconductor investigated by transmission electron microscopy The structure of the cryoalloys CO 2 -Kr has been studied in the entire range of relative concentrations by means of transmission electron diffraction. Gaseous samples were deposited from a tank at room temperature onto substrates cooled to 30 K. The filling channel was thermally insulated from the cryogenic screens. An anomalous dependence of the lattice parameter a on the molar content x of krypton in the initial gas mixture was observed; specifically, the function a͑x͒ contains a section which can be regarded as a minimum to within the limits of error. The maximum solubility of the krypton in the carbon dioxide crystal is 38 mol. %, and the solubility of CO 2 in a Kr crystal is low. The experimental data taken together give us a basis for supposing that the phase composition as a function of x has the following regions: 1͒ 0 ഛ x ഛ 0.38-regular solution of Kr in CO 2 ; 0.38ഛ x ഛ 0.6-mixture of a regular solution with critical concentration x cr = 0.38 and nano inclusions of almost pure Kr; 3͒ 0.6ഛ x ഛ 1-mixture of almost pure Kr with nano inclusions of a solution with x cr . A theoretical explanation is given for the anomalous behavior of the function a͑x͒ for x Շ 20 mol. %; the explanation is based on a cluster model and takes account of three mechanisms of interaction of Kr clusters with the crystalline environment of CO 2 . FIG. 1. Electron diffraction patterns of the solid mixtures CO 2 -Kr on a substrate consisting of amorphous carbon at T = 30 K: 2.5 mol. % Kr ͑a͒; 10 mole % Kr ͑b͒; 59 mol. % Kr ͑c͒; 70 mol. % Kr ͑d͒. Low Temp. Phys. 36 ͑3͒, March 2010 Danchuk et al. 255

Nanocrystalline Cubic Phase Scandium-Stabilized Zirconia Thin Films

“…Up to 3.5 mol% Sc 2 O 3 content (see the grey region in Figure 4 ), the ScSZ films are characterized by the monoclinic (P121/c1) phase with an intense halo. Based on the regularity of the ScSZ sold alloy, at low concentrations, single scandium atoms (having neighbors in the first coordination sphere of only zirconium atoms) dominate ( Supplementary Materials Figure S6 ) by analogy with the cluster approach developed by the authors [ 57 , 58 , 59 ] for close-packed solids. This does not favor the formation of fcc phase regions.…”

“…It results in an increase in the energy of adatoms in the diffuse layer and the substrate temperature, which also contributes to the coalescence of nuclei and CSR growth. According to Vegard's law [60], the absence of the LP response to a change in concentration is one of the criteria of the SS decomposition process [58]. Facing the insignificant difference in the ionic radii of Sc 3+ and Zr 4+ , 87 and 84 pm, correspondingly [23], continuous changes in the number of oxygen vacancies, and the presence of only fcc reflections on the XRD patterns, the statement about the phase heterogeneity is not indisputable.…”