Ion Beam Mixing of High-Tc Superconductor Components.

1988 ◽  
Vol 128 ◽  
Author(s):  
P. Borgesen ◽  
D. A. Lilienfeld
Keyword(s):  
Ion Beam ◽  
Superconducting Thin Films ◽  
Ion Beam Mixing ◽  
High Tc ◽  
Fundamental Interest ◽  
High Tc Superconductor ◽  
Wide Range ◽  
Mixing Rates ◽  
The Individual ◽  
Binary Mixing

ABSTRACTThe design of the necessary multilayer structures for producing superconducting thin films by ion beam mixing methods requires, among others, the knowledge of the individual (binary) mixing rates. In order to measure these, various combinations of Y, Ba, Cu, and Bi were irradiated with 600 keV Xe-ions at 80K and 300K. The systems exhibited a wide range of mixing behaviors which are also of fundamental interest. Ba and Cu readily formed the BaCu phase, and further mixing with Cu progressed only via binary collision mechanisms. At 80K Cu and Y were rapidly mixed in any ratio by thermal spikes, whereas a Cu rich sample rapidly formed the Cu6Y phase at 300K. Ba could not be mixed into Y or a Y-Cu mixture. Finally, irradiation of polycrystalline layers of Cu and Bi apparently lead to rapid motion of Bi along grainboundaries at both temperatures.

Ion-beam etching as a technique for preparation of high-Tc superconductor microtips for field-ion microscopy

1990 ◽  
Vol 231 (1-2) ◽  
pp. 240-246
Author(s):  
E.I. Givargizov ◽  
A.N. Stepanova ◽  
A.A. Volobuev ◽  
A.I. Pankrashov ◽  
V.A. Yakimov ◽  
...  
Keyword(s):  
Ion Beam ◽  
Ion Beam Etching ◽  
High Tc ◽  
Field Ion Microscopy ◽  
High Tc Superconductor ◽  
Ion Microscopy

Why does Hydrogen Loss Rate Correlate with How Strongly Hydrogen Inhibits Ion Beam Mixing?

1989 ◽  
Vol 157 ◽  
Author(s):  
R. E. Wistrom ◽  
P. Borgesen
Keyword(s):  
Loss Rate ◽  
Ion Beam ◽  
Ion Beam Mixing ◽  
Mixing Rates ◽  
Loss Rates

ABSTRACTPrevious studies have shown that the presence of hydrogen in multilayer samples containing Ti reduces ion beam mixing rates. The present study sought to determine why the magnitude of this effect depends on which metal is mixed into Ti and why it is correlated to the rate at which hydrogen leaves the sample during mixing. Hydrogen loss rates of multilayers were compared with those of bilayer samples designed to minimize the effect of mixing. For bilayers, hydrogen loss rates were smaller and did not depend on which metal was mixed into Ti in the same way that multilayer loss rates do. This suggests that hydrogen leaves the multilayer samples because it is bound less strongly in the mixed regions than in the Ti. The primary cause of hydrogen loss is mixing rather than ion beam induced desorption.

Temperature Dependence of Ion Beam Mixing in Al

1981 ◽  
Vol 7 ◽  
Author(s):  
S.T. Picraux ◽  
D. M. Follstaedt ◽  
J. Delafond
Keyword(s):  
Low Temperatures ◽  
Driving Forces ◽  
Ion Beam ◽  
Slow Motion ◽  
Ion Beam Mixing ◽  
Depth Profiles ◽  
Mixing Rates ◽  
Atomic Mixing ◽  
Concentration Depth Profiles

ABSTRACTThe atomic mixing of evaporated Al/Sb films and of Al/Ag films on Al<110> crystal substrates by 400 keV Xe ion beams has been investigated. Concentration depth profiles were measured in situ by 1.5 MeV He scattering as a function of Xe fluence from 2 to 32×1015 Xe/cm2. The initial mixing rates are similar at 85 and 300 K; mixing proceeds by rapid motion of Al (≈15 Al/Xe) into and uniformly through the thickness of the Sb film and by a slow motion of Sb (≈0.5 Sb/Xe) into the Al<110> substrate. More rapid Sb mixing into Al occurs for polycrystalline Al. The rate for Al into Sb slows at concentrations approaching the stable AlSb phase. Appreciably higher rates of Sb mixing into Al (2.2 to 2.8 Sb/Xe) occur at 575 K. Mixing rates for the highly soluble system, Al/Ag, are compared to the nearly insoluble Al/Sb at 85 and 300 K. Appreciably higher rates are found for Ag than for Sb, suggesting the influence of chemical driving forces even at these low temperatures.

scholarly journals Mixing of Al Into Uranium Silicides Reactor Fuels

1996 ◽  
Vol 439 ◽  
Author(s):  
Fu-Rong Ding ◽  
R. C. Birtcher ◽  
B. J. Kestel ◽  
P. M. Baldo
Keyword(s):  
Ion Beam ◽  
High Dose ◽  
Ion Beam Mixing ◽  
Dose Irradiation ◽  
Fuel Burn ◽  
Fission Gas ◽  
Mixing Rates ◽  
Radiation Induced ◽  
And Diffusion ◽  
Swelling Behaviors

AbstractSEM observations have shown that irradiation induced interaction of the aluminum cladding with uranium silicide reactor fuels strongly affects both fission gas and fuel swelling behaviors during fuel burn-up. We have used ion beam mixing, by 1.5 MeV Kr, to study this phenomena. RBS and the 27 A1( p, γ) 28 Si resonance nuclear reaction to was used to measure radiation induced mixing of Al into U3Si and U3Si2 after irradiation at 300γ;C.Initially U mixes into the Al layer and Al mixes into the U3 Si. At a low doses, the Al layer is converted into Ual4 type compound while near the interface the phase U(Al93 Si. 07 )3 grows. Under irradiation, Al diffuses out of the Ual4 surface layer, and the lower density ternary, which is stable under irradiation, is the final product. Al mixing into U3 Si2 is slower than in U3 Si, but after high dose irradiation the Al concentration extends much father into the bulk. In both systems Al mixing and diffusion is controlled by phase formation and growth. The Al mixing rates into the two alloys are similar to that of Al into pure uranium where similar aluminide phases are formed.

Ion beam sputtering deposition and etching of high Tc YBCO superconducting thin films

Vacuum ◽  
1991 ◽  
Vol 42 (16) ◽  
pp. 1062-1063
Author(s):  
Zhao Xingrong ◽  
Hao Jianhua ◽  
Zhou Fangqiao ◽  
Sun Handong ◽  
Wang Lingjie ◽  
...  
Keyword(s):  
Thin Films ◽  
Ion Beam ◽  
Superconducting Thin Films ◽  
Ion Beam Sputtering ◽  
High Tc ◽  
Sputtering Deposition ◽  
Beam Sputtering

The influence of hydrogen on ion beam mixing of multilayer films

1989 ◽  
Vol 4 (4) ◽  
pp. 821-833 ◽  
Author(s):  
P. B⊘rgesen ◽  
R. E. Wistrom ◽  
H. H. Johnson ◽  
D. A. Lilienfeld
Keyword(s):  
Room Temperature ◽  
Ion Beam ◽  
Liquid Nitrogen Temperature ◽  
Heat Of Mixing ◽  
Mixing Rate ◽  
Ion Beam Mixing ◽  
Thermal Spike Model ◽  
Spike Model ◽  
Mixing Rates ◽  
Lower Temperature

Previous qualitative studies of ion beam mixing of Ni–Ti and Fe–Ti multilayers at room temperature have shown the Ni–Ti samples to mix considerably faster than the Fe–Ti, in apparent contrast with theory. Furthermore, the Fe–Ti mixing was strongly inhibited by previous charging of the sample with hydrogen, whereas only a small effect was seen for Ni–Ti. We have quantified the mixing and extended the study to four more systems (Al–Ti. Co–Ti, Cu–Ti, and Pd–Ti) and lower temperatures. This allows some important conclusions to be drawn. Predictions based on a thermal spike model underestimate the larger room temperature mixing rates (Cu–Ti, Ni–Ti, and Pd–Ti), apparently because of contributions from a temperature dependent mechanism such as radiation enhanced diffusion. The lower mixing rates (Fe–Ti, Co–Ti, and Ni–Ti at ∼80 K) are overestimated by a factor of 2–3.5, possibly because of hydrogen contamination of the as-deposited samples. For the Al–Ti sample, the experimental mixing rate was in good agreement with predictions. Except for the Cu–Ti sample, results were seen to vary with heat of solution, rather than heat of mixing, suggesting significant contributions from the lower temperature after-spike regime. Hydrogen charging was found to reduce the Fe–Ti mixing rate by a factor of 7 at room temperature, whereas the Co–Ti and Ni–Ti rates were only reduced by a factor of 2, and the mixing of the Pd–Ti was influenced very little. Near liquid nitrogen temperature the Ni–Ti mixing rate was more strongly reduced (by a factor of 3–4). Our results suggest that the original hydrogen contamination in as-deposited samples may also cause significant reduction of mixing rates in some materials.

Formation of YBaCuO superconducting thin films by ion beam mixing

Vacuum ◽  
1991 ◽  
Vol 42 (16) ◽  
pp. 1064
Author(s):  
Fan Xiangjun ◽  
Pen Youqui ◽  
Guo Huaixi ◽  
Li Hongtao ◽  
Liu Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Ion Beam ◽  
Superconducting Thin Films ◽  
Ion Beam Mixing

Ion-beam mixing and thermal annealing of Al–Nb and Al–Ta thin films

1988 ◽  
Vol 3 (6) ◽  
pp. 1082-1088 ◽  
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. G. Mendiratta ◽  
P. R. Subramanian ◽  
D. M. Dimiduk
Keyword(s):  
Thin Films ◽  
Thermal Annealing ◽  
Phase Formation ◽  
Ion Beam ◽  
Amorphous Films ◽  
Individual Layer ◽  
Ion Beam Mixing ◽  
Partial Reaction ◽  
Complete Reaction ◽  
The Individual

Ion-beam mixing and thermal annealing of thin, alternating layers of Al and Nb, as well as Al and Ta, were investigated by selected area diffraction and Rutherford backscattcring. The individual layer thicknesses were adjusted to obtain the overall compositions as Al3Nb and Al3Ta. The films were ion mixed with 1 MeV Au+ ions at a dose of 1 × 1016 ions cm−2. Uniform mixing and amorphization were achieved for both Al−Nb and Al−Ta systems. Equilibrium crystalline A13Nb and Al13Ta phases were formed after annealing of ion mixed amorphous films at 400 °C for 1 h. Unmixed films, however, remained unreacted at 400 °C for 1 h. Partial reaction was observed in the unmixed film of Al–Nb at 400 °C for 6 h. After annealing at 500 °C for 1 h, a complete reaction and formation of Al3Nb and Al3Ta phases in the respective films were observed. The influence of thermodynamics on the phase formation by ion mixing and thermal annealing is discussed.

Ion-beam mixing in energetic collision cascades: Thermal-spike model and experiments

1999 ◽  
Vol 14 (1) ◽  
pp. 281-285 ◽  
Author(s):  
Byungwoo Park ◽  
Hyukjae Lee
Keyword(s):  
Ion Beam ◽  
Atomic Diffusion ◽  
Heat Of Mixing ◽  
Thermal Spike ◽  
Mixing Rate ◽  
Ion Beam Mixing ◽  
Nuclear Stopping ◽  
Thermal Spike Model ◽  
Spike Model ◽  
Mixing Rates

A phenomenological model of ion-beam mixing during energetic collision cascades is developed, based on the concept of a thermal spike, to correctly predict that the mixing rate Dt depends linearly on nuclear stopping power (instead of a power-law dependence), and is correlated with a heat of mixing (analogous to Darken's relation). Previous ion-beam mixing experiments from 25 different metallic bilayers agree well with the model's predictions: mixing rates (Dt)/(ion-dose) ∼ 1 nm4, and an activation enthalpy of approximately 1 eV for atomic diffusion in liquid-like cascades.

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