Evidence for solid krypton bubbles in copper, nickel and gold at 293K

Evans, John H.; Mazey, D.J.

doi:10.1088/0305-4608/15/1/001

Cited by 167 publications

(45 citation statements)

References 13 publications

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“…From direct diffraction measurements of the unit cell parameters for the noble gases, the pressure in the inclusions could be determined using appropriate equations of state. For solid noble gas inclusions formed in a series of metals the pressure was found to lie in a range from about 1 to 10 GPa depending on the size of the inclusions and the properties of the matrix (Evans and Mazey 1985;Templier et al, 1986a). In general, the pressure, p, in the inclusions could be expressed by…”

Section: Solid Noble Gas Inclusionsmentioning

confidence: 99%

Nanoscale lead and noble gas inclusions in aluminum: Structures and properties

Johnson

Andersen

Dahmen

2004

Microscopy Res & Technique

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Transmission electron microscopy has been used for structural and physical characterization of nanoscale inclusions of lead and noble gases in aluminum. When the inclusion sizes approach nanoscale dimensions, many of their properties are seen to deviate from similar properties in bulk and in most cases the deviations will increase as the inclusion sizes decrease. Binary alloys of lead and noble gases with aluminum are characterized by extremely low mutual solubilities and inclusions will, therefore, exist as practically pure components embedded in the aluminum matrix. Furthermore, the thermal vacancy mobility in aluminum at and above room temperature is sufficiently high to accommodate volume strains associated with the inclusions thus leading to virtually strain free crystals. The inclusions grow in parallel cube alignment with the aluminum matrix and have a cuboctahedral shape, which reflects directly the anisotropy of the interfacial energies. Inclusions in grain boundaries can have single crystalline or bicrystalline morphology that can be explained from a generalized Wulff analysis such as the xi-vector construction. The inclusions have been found to display a variety of nanoscale features such as high Laplace pressure, size-dependent superheating during melting, deviations from the Wulff shape displaying magic size effects, a shape dependence of edge energy, and so on. All these effects have been observed and monitored by TEM using conventional imaging conditions and high-resolution conditions in combination with in-situ analysis at elevated temperatures.

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Section: Solid Noble Gas Inclusionsmentioning

confidence: 99%

Nanoscale lead and noble gas inclusions in aluminum: Structures and properties

Johnson

Andersen

Dahmen

2004

Microscopy Res & Technique

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“…In this work, we have created solid Kr nanoclusters as observed by means of transmission electron microscopy ͑TEM͒ and investigated positron trapping in this host-nanocluster system. Solid Kr clusters created by means of ion implantation were already observed in the metals Ti, Ni, Cu, Mo, and Au, 13,14 in graphite and Grafoil, 15 and once in MgO. 16 Most of the work on solid Kr mentioned above concerns the analysis of diffraction patterns in TEM and x-ray absorption studies.…”

Section: Introductionmentioning

confidence: 99%

Formation of solid Kr nanoclusters in MgO

et al. 2003

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The phenomenon of positron confinement enables us to investigate the electronic structure of nanoclusters embedded in host matrices. Solid Kr nanoclusters are a very interesting subject of investigation because of the very low predicted value of the positron affinity of bulk Kr. In this work, positron trapping in solid Kr nanoclusters embedded in MgO is investigated. The Kr nanoclusters were created by means of 280 keV Kr ion implantation in single crystals of MgO͑100͒ and subsequent thermal annealing at a temperature of 1100 K. The nanoclusters were observed by cross-sectional transmission electron microscopy in high-resolution mode. The fcc Kr nanoclusters are rectangularly shaped with sizes of 2 to 5 nm and are in a cube-on-cube orientation relationship with the MgO host matrix. From the Moiré fringes in high-resolution recordings, the lattice parameter of the solid Kr was deduced and found to vary from 5.3 to 5.8 Å. The corresponding pressures are 0.6 -2.5 GPa as found using the Ronchi equation of state. The relationship between lattice parameter and cluster size was investigated and it was found that the lattice parameter increases linearly with increasing nanocluster size. The defect evolution during annealing was monitored by means optical absorption spectroscopy and positron beam analysis. No evidence of positron trapping was found despite the very low positron affinity of solid Kr. Alternative definitions of the positron affinity are proposed for application to insulator materials.

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“…The noble gas cluster geometry in a-C is still unknown since we are working with an amorphous material and the cluster geometry depends highly on the host matrix structure as it has been showed [11][12][13][14]. However, as those films are graphite-like it is reasonable to think that the noble gas clusters are trapped between graphitic planes [15].…”

Section: Resultsmentioning

confidence: 99%

“…It has been observed that when xenon is implanted at room temperature with energies in the range of about 200 to 400KeV it agglomerates in form of solid crystalline clusters when a concentration of about 4% xenon is reached. The crystalline cluster phase depends on the host matrix phase, being fcc for fcc and bcc [11][12][13] matrices and hcp for hcp [14] ones. The xenon lattice constant depends on the chemical nature of the host matrix, once different elements can exerts different pressures on the implanted elements.…”

Section: Introductionmentioning

confidence: 99%

XAS of high pressure Xe clusters in amorphous carbon and computational simulation for the fcc and hcp xenon crystalline phases

Oliveira¹,

Marques²

2006

Braz. J. Phys.

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We report the investigation of Xe clusters in amorphous carbon by x-ray absorption spectroscopy (XAS) to understand the properties of solid xenon. Measurements have been performed on xenon L 3 absorption edge at room temperature (300K). Using computational XANES calculation for fcc and hcp structures it was possible to study the XANES fine structure origin and a relation between the x-ray absorption near edge structure and the lattice constant. Comparing those results with our experimental data we determined that the XAS fine near edge structure has a specific behavior for solid xenon and does not have this behavior for gas Xe end Xe diluted in others chemical elements matrices.

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Evidence for solid krypton bubbles in copper, nickel and gold at 293K

Cited by 167 publications

References 13 publications

Nanoscale lead and noble gas inclusions in aluminum: Structures and properties

Nanoscale lead and noble gas inclusions in aluminum: Structures and properties

Formation of solid Kr nanoclusters in MgO

XAS of high pressure Xe clusters in amorphous carbon and computational simulation for the fcc and hcp xenon crystalline phases

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