A defect model for ion-induced crystallization and amorphization

1988 ◽  
Vol 3 (6) ◽  
pp. 1218-1226 ◽  
Author(s):  
K. A. Jackson
Keyword(s):  
Amorphous Phase ◽  
Ion Fluxes ◽  
Experimental Investigations ◽  
Interface Motion ◽  
Amorphous Phases ◽  
Single Defect ◽  
Reciprocal Temperature ◽  
Induced Motion ◽  
Arrhenius Temperature Dependence ◽  
Arrhenius Temperature

Extensive experimental investigations have been reported on the ion-induced motion of the interface between the crystalline and amorphous phases of silicon. The crystal grows into the amorphous phase at low ion fluxes and high temperatures. The amorphous phase grows into the crystal at high ion fluxes and low temperatures. The experimental observations are shown to fit a model based on a single defect. The concentration of this defect decays by binary recombination, this is, two of the defects annihilate one another. The model accounts for the linear relationship between interface motion and reciprocal temperature, for the Arrhenius temperature dependence of the flux at which no interface motion occurs, and for the temperature independence of the crossover frequency observed in beam pulsing experiments. The defect on which this model is based has a motion energy of 1.2 eV. Assuming that the same defect is also responsible for thermal recrystallization of the amorphous phase gives a formation energy of 1.5 eV for the defect. The defect is believed to be a dangling bond in the amorphous phase.

ION Induced Crystallization and Amorphization of Silicon

1989 ◽  
Vol 147 ◽  
Author(s):  
Kenneth A. Jackson
Keyword(s):  
Amorphous Phase ◽  
Experimental Investigations ◽  
Dangling Bond ◽  
Interface Motion ◽  
Amorphous Phases ◽  
Model Based ◽  
Single Defect ◽  
Motion Energy ◽  
Induced Motion ◽  
Induced Crystallization

AbstractExtensive experimental investigations which have been reported on the ion-induced motion of the interface between the crystalline and amorphous phases of silicon are shown to fit a model based on a single defect. The model accounts for the temperature and flux dependence of the interface motion. The defects annihilate each other by binary recombination, and have a motion energy of 1.2 eV. The defect is believed to be the dangling bond in the amorphous phase.

Elastic After-Effect Due to Oxygen Relaxation in Yba2Cu3O7−δAbove Tc

1990 ◽  
Vol 209 ◽  
Author(s):  
J. R. Cost ◽  
P. E. Armstrong ◽  
R. B. Poeppel ◽  
J. T. Stanley
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Internal Friction ◽  
Relaxation Times ◽  
Tracer Diffusion ◽  
Induced Motion ◽  
Arrhenius Temperature Dependence ◽  
After Effect ◽  
Friction Measurements ◽  
Arrhenius Temperature

ABSTRACTIsothermal elastic after-effect measurements to obtain relaxation times for the stress-induced motion of oxygen in YBa2Cu3O7−δ have been made from 50°C to 110°C. These results extend our previous internal friction measurements of the same oxygen relaxation to lower temperatures. The combined results, which cover nine orders of magnitude in relaxation time, show a classical Arrhenius temperature dependence, activation energy Q−1.13±0.01 eV and attempt frequency τ0−1.6×10−13 s (log τ0−.12.79±0.13). The mechanism of the relaxation is considered to be stress-induced ordering of oxygen atoms on theCuO basal plane. Diffusivities obtained from these results are compared with those from tracer diffusion of oxygen.

Self-diffusion of Ag+ and Na+ in molten Ca(NO3)2-KNO3

1972 ◽  
Vol 25 (8) ◽  
pp. 1613 ◽  
Author(s):  
BJ Welch ◽  
CA Angell
Keyword(s):  
Electrical Conductance ◽  
Ionic Species ◽  
Tracer Diffusion ◽  
Dilute Solution ◽  
Self Diffusion ◽  
Capillary Method ◽  
Arrhenius Temperature Dependence ◽  
Radio Tracer ◽  
Tracer Diffusion Coefficients ◽  
Arrhenius Temperature

In order to explore the behaviour of diffusing ionic species in a molten salt in which non-Arrhenius behaviour of other transport properties is established, the diffusivities in dilute solution of Ag+ and Na+ in 38.1 mol% Ca(NO3)2+ 61.9 mol% KNO3 have been measured. For both ions limited radio-tracer diffusion coefficients, determined using a diffusion-out-of-capillary method, are reported. D(Ag+) has also been measured by chronopotentiometry, by which means the range and reliability of the measurements were considerably extended. Chronopotentiometric and tracer data agree within expected errors of measurement. Both ionic diffusivities show a non-Arrhenius temperature dependence which is indistinguishable in magnitude from that of the electrical conductance of the solvent melt.

scholarly journals DC conductivity of polyethylene and crosslinked polyethylene measured with a dynamic temperature program

2017 ◽  
Author(s):  
Hossein Ghorbani ◽  
Carl-Olof Olsson ◽  
Marc Jeroense
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Thermal Conditions ◽  
Dc Conductivity ◽  
Protective Film ◽  
Dynamic Temperature ◽  
Operation Conditions ◽  
Heating And Cooling ◽  
Arrhenius Temperature Dependence ◽  
Arrhenius Temperature

<p>Electrical conductivity of HVDC cable insulation materials is important for its function. It is very practical to evaluate this parameter by DC conductivity measurements on press molded polymeric plates samples. While in real operation conditions, the insulation undergoes both static and dynamic thermal conditions, most of the published research in this area is still focused only on steady state thermal conditions. In this work, the focus is instead on the behavior of electrical conductivity under dynamic thermal conditions. Press molded XLPE and LDPE plate samples with different preparations are tested under 25 kV/mm DC field with a dynamic temperature profile ranging from room temperature to 90 °C.<br />It was discovered that in many cases, the measured conductivity during dynamic measurements strongly deviates from the expected Arrhenius temperature dependence; instead the conductivity shows a nonmonotonic<br />temperature dependence manifested as conductivity peaks during heating and cooling. The behavior is found to be strongly related to the type of protective film used during press molding of the sample; further degassing leads to a reduction of the nonmonotonic temperature dependence and with long<br />degassing the behavior tends to the expected Arrhenius temperature dependence.</p>

scholarly journals Intrinsic electrical properties of cable bacteria reveal an Arrhenius temperature dependence

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Robin Bonné ◽  
Ji-Ling Hou ◽  
Jeroen Hustings ◽  
Koen Wouters ◽  
Mathijs Meert ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electrical Properties ◽  
Temperature Dependence ◽  
Electrical Characterization ◽  
Electrical Circuit ◽  
Parallel Fibre ◽  
Thermally Activated ◽  
Arrhenius Temperature Dependence ◽  
Equivalent Electrical Circuit Model ◽  
Arrhenius Temperature

AbstractFilamentous cable bacteria exhibit long-range electron transport over centimetre-scale distances, which takes place in a parallel fibre structure with high electrical conductivity. Still, the underlying electron transport mechanism remains undisclosed. Here we determine the intrinsic electrical properties of the conductive fibres in cable bacteria from a material science perspective. Impedance spectroscopy provides an equivalent electrical circuit model, which demonstrates that dry cable bacteria filaments function as resistive biological wires. Temperature-dependent electrical characterization reveals that the conductivity can be described with an Arrhenius-type relation over a broad temperature range (− 195 °C to + 50 °C), demonstrating that charge transport is thermally activated with a low activation energy of 40–50 meV. Furthermore, when cable bacterium filaments are utilized as the channel in a field-effect transistor, they show n-type transport suggesting that electrons are the charge carriers. Electron mobility values are ~ 0.1 cm2/Vs at room temperature and display a similar Arrhenius temperature dependence as conductivity. Overall, our results demonstrate that the intrinsic electrical properties of the conductive fibres in cable bacteria are comparable to synthetic organic semiconductor materials, and so they offer promising perspectives for both fundamental studies of biological electron transport as well as applications in microbial electrochemical technologies and bioelectronics.

scholarly journals Vitrification decoupling from α-relaxation in a metallic glass

2020 ◽  
Vol 6 (17) ◽  
pp. eaay1454
Author(s):  
Xavier Monnier ◽  
Daniele Cangialosi ◽  
Beatrice Ruta ◽  
Ralf Busch ◽  
Isabella Gallino
Keyword(s):  
Metallic Glass ◽  
Temperature Dependence ◽  
Metallic Glasses ◽  
Materials Science ◽  
Scanning Calorimetry ◽  
Fictive Temperature ◽  
Fundamental Properties ◽  
Fast Scanning Calorimetry ◽  
Arrhenius Temperature Dependence ◽  
Arrhenius Temperature

Understanding how glasses form, the so-called vitrification, remains a major challenge in materials science. Here, we study vitrification kinetics, in terms of the limiting fictive temperature, and atomic mobility related to the α-relaxation of an Au-based bulk metallic glass former by fast scanning calorimetry. We show that the time scale of the α-relaxation exhibits super-Arrhenius temperature dependence typical of fragile liquids. In contrast, vitrification kinetics displays milder temperature dependence at moderate undercooling, and thereby, vitrification takes place at temperatures lower than those associated to the α-relaxation. This finding challenges the paradigmatic view based on a one-to-one correlation between vitrification, leading to the glass transition, and the α-relaxation. We provide arguments that at moderate to deep undercooling, other atomic motions, which are not involved in the α-relaxation and that originate from the heterogeneous dynamics in metallic glasses, contribute to vitrification. Implications from the viewpoint of glasses fundamental properties are discussed.

Two Species/Nonideal Solution Model for Amorphous/Amorphous Phase Transitions

1996 ◽  
Vol 455 ◽  
Author(s):  
Cornelius T. Moynihan
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Critical Temperature ◽  
Amorphous Phase ◽  
Thermodynamic Model ◽  
Critical Pressure ◽  
Solution Model ◽  
Amorphous Phases ◽  
First Order ◽  
Temperature And Pressure

ABSTRACTA simple macroscopic thermodynamic model for first order transitions between two amorphous phases in a one component liquid is reviewed, augmented and evaluated. The model presumes the existence in the liquid of two species, whose concentrations are temperature and pressure dependent and which form a solution with large, positive deviations from ideality. Application of the model to recent data indicates that water can undergo an amorphous/amorphous phase transition below a critical temperature Tc of 217K and above a critical pressure Pc of 380 atm.

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