Solute Trapping of Ge in Al

1990 ◽  
Vol 205 ◽  
Author(s):  
Patrick M. Smith ◽  
Jeffrey A. West ◽  
Michael J. Aziz
Keyword(s):  
Film Growth ◽  
Depth Profiling ◽  
Pulsed Laser ◽  
Significant Degree ◽  
Al Alloys ◽  
Continuous Growth ◽  
Solute Trapping ◽  
Conductance Technique ◽  
Lateral Film

AbstractPartitioning during rapid solidification of dilute Al-Ge alloys has been investigated. Implanted thin films of Al have been pulsed-laser melted to obtain solidification at velocities in the range of 0.01 m/s to 3.3 m/s, as measured by the transient conductance technique. Previous and subsequent Rutherford Backscattering depth profiling of the Ge solute in the Al alloys has been used to determine the nonequilibrium partition coefficient k. A significant degree of lateral film growth during solidification confines determination of k to the placing of an upper bound of 0.22 on k for solidification velocities in this range. We place a lower limit of 10m/s on the “diffusive velocity,” which locates the transition from solute paritioning to solute trapping in the Continuous Growth Model.

Solute Trapping in Metals

1992 ◽  
Vol 279 ◽  
Author(s):  
Patrick M. Smith ◽  
Riccardo Reitanot ◽  
Michael J. Aziz
Keyword(s):  
Partition Coefficient ◽  
Growth Model ◽  
Solidification Velocity ◽  
Continuous Growth ◽  
Solute Trapping ◽  
Solute Partitioning ◽  
Equilibrium Partition ◽  
Conductance Technique ◽  
Equilibrium Partition Coefficient ◽  
Alloy Properties

ABSTRACTMany of the advances in rapid solidification processing of metallic alloys exploit the trapping of solute which occurs at high solidification velocities. The difficulty of performing experiments which measure such high solidification velocities in metals has until now prevented accurate measurements of solute trapping in these systems. We have observed the transition from near-equilibrium solute partitioning to solute trapping during solidification at m/s velocities in aluminum alloys, and have compared the predictions of various solute trapping models. Aluminum thin films deposited on insulators were ion-implanted with Sn, Cu, Ge, and In, and were pulsed-laser melted; plane-front solidification was achieved, and regrowth velocities of 0.6 m/s to 5 m/s were measured with the transient conductance technique. Of the existing solute trapping models, the Continuous Growth Model of Aziz was found to fit the observed dependence of the partition coefficient on solidification velocity more closely than any other single-parameter model. The diffusive speed, which locates the transition from solute partitioning to solute trapping, was found to vary from 6 m/s to 38 m/s for various solutes in aluminum. We have examined correlations between the diffusive speed in the Continuous Growth Model and known alloy properties in order to allow better estimates of the diffusive speed to be made for alloy systems in which it has not been measured; the relation between the diffusive speed and the equilibrium partition coefficient will be discussed.

Test of Kinetic Models for Interface Velocity, Temperature, and Solute Trapping in Rapid Solidification

1995 ◽  
Vol 398 ◽  
Author(s):  
J.A. Kittl ◽  
M.J. Aziz ◽  
D.P. Brunco ◽  
M.O. Thompson
Keyword(s):  
Rapid Solidification ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Alloy System ◽  
Solute Drag ◽  
Temperature Function ◽  
Continuous Growth ◽  
Solute Trapping ◽  
Interface Kinetics ◽  
Test Models

ABSTRACTDuring rapid solidification, deviations from local interfacial equilibrium are manifested by solute trapping and interfacial undercooling. Both the solute trapping function and the interface velocity-temperature function have been measured in the Si:As alloy system following pulsed laser melting, permitting us to test models for nonequilibrium interface kinetics. The results are consistent with the Continuous Growth Model “without solute drag” of Aziz and Kaplan and are inconsistent with models that incorporate solute drag effects during solidification.

Tracing the origin of oxygen for La0.6Sr0.4MnO3thin film growth by pulsed laser deposition

2015 ◽  
Vol 49 (4) ◽  
pp. 045201 ◽  
Author(s):  
J Chen ◽  
M Döbeli ◽  
D Stender ◽  
M M Lee ◽  
K Conder ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Pulsed Laser ◽  
Laser Deposition

Microstructure of Compositionally Graded PZT films Grown by Pulsed Laser Deposition

2008 ◽  
Vol 14 (S3) ◽  
pp. 53-56
Author(s):  
S.A.S. Rodrigues ◽  
A. Khodorov ◽  
M. Pereira ◽  
M.J.M. Gomes
Keyword(s):  
Pulsed Laser Deposition ◽  
Lead Zirconate Titanate ◽  
Film Growth ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Lead Zirconate ◽  
Laser Deposition ◽  
Composition Gradient ◽  
Complex Structures ◽  
Pzt Films

Ferroelectric films with a composition gradient have attracted much attention because of their large polarization offset present in the hysteresis loops. Lead Zirconate Titanate (PZT) films were deposited on Pt/TiO2/SiO2/Si substrates by Pulsed Laser Deposition (PLD) technique, using a Nd:YAG laser (Surelite) with a source pulse wavelength of 1064 nm and duration of 5-7 ns delivering an energy of 320 mJ per pulse and a laser fluence energy about 20 J/cm2. The film growth is performed in O2 atmosphere (0,40 mbar) while the substrate is heated at 600°C by a quartz lamp. Starting from ceramic targets based on PZT compositions and containing 5% mol. of excess of PbO to compensate the lead evaporation during heat treatment, three films with different compositions Zr/Ti 55/45, 65/35 and 92/8, and two types of complex structures were produced. These complex structures are in the case of the up-graded structure (UpG), with PZT (92/8) at the bottom, PZT (65/35) on middle and PZT (55/45) on the top, and for down-graded (DoG) one, that order is reversed.

Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite and Nanocrystal-film

2011 ◽  
Vol 1305 ◽  
Author(s):  
Ikurou Umezu ◽  
Shunto Okubo ◽  
Akira Sugimura
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Hydrogen Gas ◽  
Gas Pressure ◽  
Spatial Confinement ◽  
The Individual ◽  
Background Gas ◽  
Non Equilibrium

ABSTRACTThe Si nanocrystal-films are prepared by pulsed laser ablation of Si target in a mixture of helium and hydrogen gas. The total gas pressure and hydrogen partial gas pressure were varied to control structure of nanocrystal-film. The surface of Si nanocrystallite was hydrogenated and degree of hydrogenation increased with increasing hydrogen partial gas pressure. The aggregate structure of nanocrystal-film depended on both the total gas pressure and the hydrogen partial gas pressure. The former and the latter alter spatial confinement of Si species during deposition and the surface hydrogenation of individual nanocrystal, respectively. Spatial confinement increases probability of collision between nanocrystals in the plume. While, surface hydrogenation prevents coalescence of nanocrystals. The individual or aggregated nanocrystals formed in the plume reach the substrate and the nanocrystal-film is deposited on the substrate. The non-equilibrium growth processes during pulsed laser ablation are essential for the formation of the surface structure and the subsequent nanocrystal-film growth. Our results indicate that the structure of nanocrystal-film depends on the probabilities of collision and coalescence between nanocrystals in the plume. These probabilities can be varied by controlling the total gas pressure and the hydrogen partial gas pressure.

ZnSe and ZnO film growth by pulsed-laser deposition

1998 ◽  
Vol 127-129 ◽  
pp. 496-499 ◽  
Author(s):  
Y.R. Ryu ◽  
S. Zhu ◽  
S.W. Han ◽  
H.W. White ◽  
P.F. Miceli ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Zno Film

scholarly journals Pulsed laser determination of surface electric charge distributions

1982 ◽  
Vol 43 (19) ◽  
pp. 687-693 ◽  
Author(s):  
C. Alquié ◽  
G. Charpak ◽  
J. Lewiner
Keyword(s):  
Electric Charge ◽  
Pulsed Laser ◽  
Charge Distributions

Laser fluorescence determination of lead in geological samples when vaporized by pulsed laser light

1992 ◽  
Vol 56 (3) ◽  
pp. 235-238 ◽  
Author(s):  
O. N. Ezhov ◽  
B. R. Kano ◽  
S. V. Oshemkov ◽  
A. A. Petrov
Keyword(s):  
Laser Light ◽  
Pulsed Laser ◽  
Laser Fluorescence ◽  
Geological Samples ◽  
Fluorescence Determination
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