Thermal vacancy formation and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>D</mml:mi><mml:mn>0</mml:mn><mml:mn /></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>ordering in nanocrystalline intermetallic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Fe</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:m

Pasquini, Luca; Rempel, А. А.; Würschum, Roland; Reimann, K.; Müller, Markus; Fultz, B.; Schaefer, H.‐E.

doi:10.1103/physrevb.63.134114

Cited by 18 publications

(12 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 Chemically sensitive free volume studies of interfaces in nanocrystalline materials by means of Doppler broadening have been initiated recently. 6,7 The present work is a first systematic in-depth study exploring the potentials of this method for chemically sensitive characterization of free volumes in a structurally complex material which develops during the various states of solid-state amorphization.…”

Section: Introductionmentioning

confidence: 99%

Chemically sensitive free-volume study of amorphization of Cu60Zr40 induced by cold rolling and folding

Puff

Rabitsch

Wilde

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

With the aim to contribute to a microscopical understanding of the processes of solid-state amorphization, the chemically sensitive technique of background—reduced Doppler broadening of positron-electron annihilation radiation in combination with positron lifetime spectroscopy and microstructural characterization is applied to a free volume study of the amorphization of Cu60Zr40 induced by consecutive folding and rolling. Starting from the constituent pure metal foils, a nanosale multilayer structure of elemental layers and amorphous interlayers develops in an intermediate state of folding and rolling, where free volumes with a Zr-rich environment occur presumably located in the hetero-interfaces between the various layers or in grain boundaries of the Cu layers. After complete intermixing and amorphization, the local chemical environment of the free volumes reflects the average chemical alloy composition. In contrast to other processes of amorphization, free volumes of the size of few missing atoms occur in the rolling-induced amorphous state. Self-consistent results from three different methods for analyzing the Doppler broadening spectra, i.e., S−W-parameter correlation, multicomponent fit, and the shape of ratio curves, demonstrate the potential of the background-reduced Doppler technique for chemically sensitive characterization of structurally complex materials on an atomic scale.

show abstract

Section: Introductionmentioning

confidence: 99%

Chemically sensitive free-volume study of amorphization of Cu60Zr40 induced by cold rolling and folding

Puff

Rabitsch

Wilde

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The transition rate  fg is understood to be proportional to D + , whose dependence on the temperature is given by If the diffusion length L + competes the size of the grain the probability of the transition rate from free to grain boundary is high. Pasquini et al [13] have shown that the trapping coefficient for the thermal vacancy shows an increasing trend as temperature rises. Further, the trapping rate is expected to be proportional to the thermal vacancy concentration.…”

Section: Resultsmentioning

confidence: 99%

“…The equation (12) has been used to obtain the mean positron lifetime in pure and doped ZnO thin films, while equation (13) has been used to calculate the S-parameter in these films.…”

Section: Formulation Of the Diffusion Trapping Modelmentioning

confidence: 99%

S-Parameter and Positron Lifetime Studies of Mn Doped Zn1-Xox

Rathore¹

2018

IJRASET

View full text Add to dashboard Cite

Zinc Oxide (ZnO) is an fascinating material and have potential applications as a transparent conductive electrodes for solar cells, light emmitting diodes as well as for gas sensors. Interaction between dopant, impurities and intrinsic defects plays an essential role to enhance the electrical and optical properties of ZnO thin films. Positron annihilation spectroscopy (PAS) is a non destructive technique to study thin films and nanocrystalline materials. The mechanism of positron annihilation in oxide thin films has been discussed in terms of diffusion of positrons inside the grain boundaries, nanovoids and thermally generated vacancies. The mean positron lifetime and S-parameter as a function of grain size in pure and Mn doped ZnO thin films has been calculated by using positron diffusion model. The samples are prepared by Spray pyrolysis method and temperature dependent measurements revels information about the presence of shallow positron traps like grain boundaries and interfacial defects. The calculations of shows that mean positron lifetime decreases as the grain grows. While the S-parameter increases with the increase in the siza of grains. This increase in  has been ascribed to the increase in the number of thermally generated vacancies at higher temperatures. diffusion can also be closely linked with thermal defect formation at higher temperatures. Thus, information regarding grain boundaries in thin films and nano composites can be gathered by DTM (diffusion Trapping Model). I. INTRODUCTIONPositron annihilation lifetime spectroscopy (PALS) serves as a unique tool for the characterization of lattice defects in materials science. While the annihilation lifetime yields characteristic information about the size of open-volume defects ranging from single atomic vacancies up to nanovoids, the kinematical Doppler-broadening of annihilation radiation tells about the local electron momentum distribution at the annihilation site. Annihilation lifetimes are monotonously related to the void size with a surprisingly low dependence on the material surrounding the void [1]. The semiconducting nanocrystalline thin films have great applications in electronic industry, solar cells, solar energy storage and biomedical industries. Among the nanocrystalline semiconducting materials the preparation and characterization of doped and undoped ZnO films has assumed much importance during recent years. ZnO is an important wide band gap semiconductor having wide applications in various fields such as transducers, gas sensors, transport conduction electrodes and surface acoustic wave devices etc. [2][3][4]. Zinc oxide (ZnO) is a material with great potential for a variety of practical applications due to the unique physical and chemical properties such as wide and di-rect energy band gap (~3.37 eV), large exciton binding energy (~60 meV), high electron mobility, high thermal conductivity, high radiation damage resistance and biocompatibility. The recent progress in nanoscaling of ZnO structures attracts also attention t...

show abstract

“…The formation of B2, L1 2 , and D0 3 order in several nanocrystalline alloys have been reported, including Ti-Al, Fe-Al, Fe-Si, Fe-Co, Ni-Al, and Cu-Au, sometimes with ternary additions. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] These studies have emphasized various aspects of defects and diffusion in nanostructured alloys, with comparisons to bulk materials. The reverse transformation, disordering a B2-ordered Fe 60 Al 40 nanocrystalline alloy during high-energy ball milling, has also been studied recently.…”

Section: Introductionmentioning

confidence: 99%

“…The reverse transformation, disordering a B2-ordered Fe 60 Al 40 nanocrystalline alloy during high-energy ball milling, has also been studied recently. 26 A number of features seem common to the reordering of chemically disordered nanocrystalline materials, in spite of differences in their methods of synthesis ͑e.g., ball milling, 10,11,15,[17][18][19][20]23,24,27 plastic deformation, 28 gas-phase condensation with compaction, 21,22 sputtering, 16 ion irradiation 29 ͒, microstructures ͑isolated clusters 16 or more typically micron-sized particles composed of nanometersized grains͒, and ordered structures. Reordering can occur at low temperatures, and involves only few jumps of nonequilibrium vacancies that were not promptly annihilated at sinks.…”

Section: Introductionmentioning

confidence: 99%