The Formation Energy of Vacancies in Aluminium and Magnesium

Tzanétakis, P.; Hillairet, J.; Revel, Gilles de

doi:10.1002/pssb.2220750205

Cited by 129 publications

(51 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This leads to the activation energy of the vacancy formation in aluminum of 63.6 kJ/mol (0.66 eV) that coincides with the measured values reported elsewhere. 2,5) From the given activation energy, the vacancy concentration in aluminum at 300 C is estimated to be about 10 À6 . Usually, the amount of hydrogen in aluminum is negligible and can be ignored with respect to vacancy concentration, because the solubility of hydrogen is about 1 ppm near the melting point.…”

Section: Resultsmentioning

confidence: 99%

“…This value nearly coincides with the formation energy reported for vacancies in magnesium. [1][2][3]5) Extrapolation of the straight solid line is denoted by the dashed line. The dotted line, obtained by subtracting the value of the dashed line from the measured points, is taken as the contribution of the vacancies bound with hydrogen, i.e.…”

Section: 3mentioning

confidence: 99%

“…It is difficult to refer to many articles on the subject of magnesium, even though the references go back 30-40 years when energetic activity was focused on lattice defects. In spite of these circumstances, there are reports of several techniques regarding the formation energy of vacancies in magnesium: 85.9 kJ/mol (0.89 eV) 1) and 76.3 kJ/mol (0.79 eV) 2) by electrical resistivity measurements with quenching from high temperatures, 78.2 kJ/mol (0.81 eV) 3) by electrical resistivity in thermal equilibrium at high temperatures, 56.0 kJ/mol (0.58 eV) 4) by dilatometry, and 86.9 kJ/mol (0.90 eV) 5) by positron annihilation. Tzanetakis et al 2) commented on the value of 56.0 kJ/mol (0.58 eV) presented by Janot et al 4) because the dilatometric measurement and the lattice constant determination were made on separate specimens which might have had different dislocation distributions.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Hydrogen on the Vacancy Formation in Magnesium

2008

View full text Add to dashboard Cite

Quenching and annealing experiments with electrical resistivity measurements were applied to magnesium to investigate the formation of thermal vacancies. Two specimens made from materials differing in impurity contents were examined. One of the specimens quenched in a methanol bath at À80C from elevated temperatures ranging from 160 C to 500 C revealed a significant decrease in electrical resistance after annealing for 10 min in the bath. Based on the annealing behaviors at low temperatures (À100 C to À60 C) after the quenching from 200 C, this decrease is thought to be due to the presence of hydrogen in solution. The other specimen, presumably containing smaller amounts of hydrogen, was quenched in iced water from elevated temperatures (200 C-560 C) which yielded results characterized by two thermal activation processes. These processes had the activation energies 54.1 kJ/mol (0.56 eV) and 89.8 kJ/mol (0.93 eV) for the lower and higher quenching temperature ranges, respectively. The former is ascribed to the formation energy of a vacancy interacting with hydrogen and the latter to the intrinsic formation energy of a vacancy. The difference between these energies, 35.7 kJ/mol (0.37 eV), is the binding energy between a vacancy and a hydrogen atom.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: 3mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Hydrogen on the Vacancy Formation in Magnesium

2008

View full text Add to dashboard Cite

show abstract

“…35,36 At these temperatures hydride formation will cease to occur and sintering will become a problem.…”

Section: Bimetallic Structuresmentioning

confidence: 99%

Templated synthesis of nickel nanoparticles: Toward heterostructured nanocomposites for efficient hydrogen storage

Nelson

2013

View full text Add to dashboard Cite

“…the separate components for the change in Gibbs free energy with respect to vacancy formation are calculated with respect to number of vacancies near the melting point [175].…”

Section: Formation Of Point Defects In Oxidesmentioning

confidence: 99%

Understanding Phonon Interactions with Defects in Functional Oxide Materials

Donovan¹

View full text Add to dashboard Cite

Understanding of nano-scale thermal transport has enabled significant advances in a wide variety of fields including microelectronics, alternative energy, optics, and many more [1][2][3][4]. Utilized in many of these applications are a class of materials known as functional oxides. These materials are oxygen compounds with specific functional properties of interest (e.g., dielectrics [5][6][7][8], piezoelectrics [9][10][11], photovoltaics [12][13][14], thermoelectrics [15][16][17][18][19]). Often it is the defects in these materials that enable functionality and, depending on the processing and operating conditions, the concentration and types of defects that are present in these materials can vary widely [20]. In this dissertation, I aim to identify the role that defects play in functional oxide materials with respect to thermal transport.The major thermal carriers in most functional oxide crystals are collective lattice vibrations, or phonons [21]. Phonon-dominated thermal conductivity is dictated by the scattering of these thermal carriers with a variety of other components or the material system, including defects in the crystal [22,23]. I concentrate on three types of defects that are common in functional oxides: boundaries, extrinsic point defects, and intrinsic point defects.Boundaries such as film boundaries and grain boundaries with nano-scale dimensions can be detrimental to the thermal conductivity of a material. As the length of the uninterrupted crystal reduces to the phonon mean free paths in the crystal, phonons will scatter readily off of nano-scale boundaries and will not be able to propagate as they would in a bulk environment. This becomes particularly relevant in technologies such as the microelectronics industry, where device size scales are well below common phonon mean free paths in the constituent materials. To study this, I turn to one of the more common functional oxides used in the microelectronics industry, BaTiO 3 .I study the effects of nano-scale grains on thin films of BaTiO 3 grown via chemical solution deposition. The films studied are 150 nm and range in grain size from 36 nm -63 nm. I show that the thermal conductivity of these nano-grained films scales with the grain size and film thickness and demonstrate agreement of this trend with analytical models. This result demonstrates that despite a complex crystal structure, there is a mean free path spectrum of phonons in BaTiO 3 that significantly exceeds the dimensions of the grains and film (contrary to the common "gray" mean 2 free path assumption seen in literature).To address the role of extrinsic point defects, or dopants, on the thermal conductivity of functional oxides, I study the effects of dysprosium doping in thin films of cadmium oxide deposited by molecular beam epitaxy. In this experiment, the addition of Dy dopants in CdO actually increases the thermal conductivity initially, owing to a reduction in the equilibrium concentration of oxygen vacancies (a type of defect that is intrinsic to all oxides). The de...

show abstract

The Formation Energy of Vacancies in Aluminium and Magnesium

Cited by 129 publications

References 13 publications

Effects of Hydrogen on the Vacancy Formation in Magnesium

Effects of Hydrogen on the Vacancy Formation in Magnesium

Templated synthesis of nickel nanoparticles: Toward heterostructured nanocomposites for efficient hydrogen storage

Understanding Phonon Interactions with Defects in Functional Oxide Materials

Contact Info

Product

Resources

About