Interstitial migration in a stress gradient

Kirsanov, V. V.; Kislitsin, S. B.; Kislitsina, E. M.

doi:10.1002/pssa.2210860121

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…This is similar to the phenomenon of wind in the atmosphere, where the wind blows from high‐pressure regions to low‐pressure regions to react to the pressure difference. Similar migration effects induced by the stress gradient were previously reported for interstitial impurities, vacancies and voids . To illustrate the impact of stress gradient on impurity migration in ECM, Figure a–c show the energy potential profile for ion migration at V = V set (point P 1 in Figure d), V = V C (bias point P 2 ) and V = V reset (bias point P 3 ), respectively.…”

supporting

confidence: 73%

Impact of the Mechanical Stress on Switching Characteristics of Electrochemical Resistive Memory

et al. 2014

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with electrode size as small as 5 nm. [ 26 ] Whereas low-power operation [ 3 ] and fast switching [ 15 ] were demonstrated in ECMs, recent experiments on ECM devices [ 25,27 ] have questioned the long-term stability of the CF, which is necessary to enable nonvolatile storage of data. To assess the switching behavior and CF stability in ECMs, the detailed evolution of electrical, chemical and mechanical forces in the CF must be understood. Figure 2 a shows the measured current-voltage ( I -V ) curve for an ECM with Ag top electrode, GeS 2 electrolyte and W bottom electrode during set and reset transition. Details about the preparation of the ECM devices can be found elsewhere. [ 15 ] The set transition from high to low resistance takes place at V set ≈ 0.3 V, while the reset transition to high resistance occurs at V reset . In the set process, the CF is fi rst formed by nucleation [ 28,29 ] followed by CF growth, [ 6,24 ] which is activated by positive ion migration as shown in Figure 2 b: metallic ions from the reactive-metal electrode (Ag) hop among localized states separated by energy barriers E A0 in amorphous GeS 2 . The electric fi eld lowers the ion-migration barrier to the value:where α = 0.3 is a barrier-lowering coeffi cient (see Figure S1 in the Supporting Information for a complete list of all model parameters used in the simulation) and V is the voltage across the electrolyte. [ 6,24,30 ] Barrier lowering enhances the hopping rate in the fi eld direction, thus increasing the growth rate of the CF diameter φ according to:where A is a pre-exponential constant proportional to cation mobility, T is the local temperature at the CF and E A was obtained from Equation 1 . In Equation 2 , E A controls ion migration in the vertical direction from top to bottom electrode, while the accumulation of defects along the CF causes growth in the radial direction, which is captured by the parameter φ (e.g., see Figure 1 c). Note that the parameter φ represents an effective CF diameter, to properly describe non-cylindrical (e.g., conical) CF shapes and the case of multiple fi laments contributing to the resistive switching. [ 12,26 ] For instance, in the case of multiple fi laments the effective diameter in Equation 2 obeys φ 2 = Σ φ i 2 , where φ i represents the diameter of the individual i -th fi lament and φ properly describes the resistance R ∝ φ −2 of the set state.To control the size of the growing CF during the set transition, the current was kept equal to a compliance value I C = 1 mA in Figure 2 a, thus resulting in a resistance of about 0.3 kΩ in the set state. The current-controlled CF growth was Resistive switching in oxides and other insulating materials provides a promising approach to nanoscale memory devices, where the stored logic state can be changed by activating/deactivating a conductive fi lament (CF). [ 1,2 ] Among resistive switching devices, the electrochemical memory (ECM) attracts strong interest because of outstanding properties such as extremely small programming current, [ 3 ] fast switching...

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confidence: 73%

Impact of the Mechanical Stress on Switching Characteristics of Electrochemical Resistive Memory

et al. 2014

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“…The reduction in the peak height by deformation would occur by either models: (i) disappearance of complexes by sweeping of moving dislocations, (ii) transformation of complexes into other complexes which do not give rise t o the relaxation peaks, by the strain field of dislocations, or (iii) disappearance of symmetry of complexes by the strain field of dislocations. The effect of stress fields on the point defect characteristics has been studied by means of computer simulation and the energy barriers against interstitial migration along the stress gradient are lower than those in unstressed crystals [6]. As shown in the isochronal annealing experiments after deformation in pre-irradiated pure specimens by means of electrical resistivity [I, 21, some interstitials in cascade zones produced by fast neutrons seem t o migrate a t 4 K by the strain field of dislocations and induce the cluster formation of interstitials, When a moving dislocation moves near a defect-solute complex, the complex may dissociate t o an unstable defect and disappear.…”

Section: Methodsmentioning

confidence: 99%

Effect of low-temperature deformation on internal friction peaks of irradiated Al alloys

Takamura¹,

Kobiyama

1986

phys. stat. sol. (a)

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The effect of deformation after fast neutron irradiation at low temperatures on the internal friction peaks is studied. The peak height in internal friction is reduced largely by deformation. The degree of reduction in the peak height with increasing degree of deformation is similar for each peak. The strain field of moving dislocations may be able to transform interstitial–solute complexes into ones having a configuration that does not give rise the relaxation peaks.

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Molecular dynamics simulation of the behavior of typical radiation defects under stress gradient field in tungsten

Fang

Liu

Gao

et al. 2021

Journal of Applied Physics

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In the fusion environment, a complex stress field is generated in materials, which affects the evolution of radiation defects. In this study, the behaviors of radiation-induced defects under the effect of stress gradient field in tungsten are carefully simulated at the atomic scale with the molecular dynamics (MD) method. It was found that the stress gradient field affects the migration properties of interstitial defects, resulting in the energy barriers changing with the stress and stress gradient. In the axial stress gradient field, the movement of the 1/2 <111> interstitial dislocation loop is significantly accelerated, and it tends to move toward the region where the stress is concentrated. Within the time scale of the classical MD simulation, the stress gradient has little effect on the migration of vacancies. These results suggested that the stress gradient would cause interstitial defects to accumulate to the region where the stress is concentrated, thereby significantly changing the properties of the tungsten materials.

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Interstitial migration in a stress gradient

Cited by 3 publications

References 6 publications

Impact of the Mechanical Stress on Switching Characteristics of Electrochemical Resistive Memory

Impact of the Mechanical Stress on Switching Characteristics of Electrochemical Resistive Memory

Effect of low-temperature deformation on internal friction peaks of irradiated Al alloys

Molecular dynamics simulation of the behavior of typical radiation defects under stress gradient field in tungsten

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