Short-Range Order and Nanocrystallization in Amorphous Zr-Ti-Cu-Ni-Al

AbstractWe have examined the effect of Ti content on the crystallization kinetics of Zr-based amorphous alloys. In Zr59Ti3Cu20Ni8Al10, annealing above the glass transition temperature produces 50-100 nm crystalline precipitates, as seen in transmission electron microscope images. In contrast, TEM images and diffraction patterns from annealed Zr54.5Ti7.5Cu20Ni8Al10 show no evidence of crystalline phase formation. Structural changes upon annealing do occur in this alloy, however, as revealed by field ion microscopy. The effect of Ti is to favor the formation of clusters of short-range order; this tendency for clustering is apparently the cause of difference in crystallization behavior between the two alloys.

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Short-range order in amorphous co-sputtered Ta-Al thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145649 ◽

1986 ◽

Vol 44 ◽

pp. 860-861

Author(s):

J.C. Barry ◽

R.S. Timsit ◽

D. Landheer

Keyword(s):

Thin Film ◽

Thin Films ◽

Electron Microscope ◽

High Resolution ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Transmission Electron ◽

Thin Film Resistors ◽

Diffraction Patterns

Tantalum-aluminium thin films have assumed considerable technological importance since the discovery in the late 1960's that the films are useful in the fabrication of thin film resistors and capacitors. It is generally claimed that these films, when prepared by co-sputtering Ta and Al, are amorphous over a range of Ta concentrations extending approximately from 15 to 75 at%, and are crystalline beyond this range. Diffuse electron diffraction patterns and ‘mottle pattern’ transmission electron micrographs are typical characteristics of the amorphous phase. In this present study we have attempted to identify any atomic short range order in the amorphous Ta-Al films and to follow the changes in this order as the Ta concentration increases across the amorphous/crystalline transition. The co-sputtered Ta-Al films of ≈100A thickness were examined in a high resolution 4000EX electron microscope (top entry, ±15°(x,y) tilt, Cs = 1.0mm ) at 400kV.

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Ordering in Ni4Mo by TEM and APFIM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012597x ◽

1987 ◽

Vol 45 ◽

pp. 214-215

Author(s):

E.A. Kenik ◽

T.A. Zagula ◽

M.K. Miller ◽

J. Bentley

Keyword(s):

Electron Irradiation ◽

Low Temperatures ◽

Short Range ◽

Atom Probe ◽

Range Order ◽

Considerable Time ◽

Probe Field ◽

Disordered Phase ◽

Transmission Electron ◽

Diffraction Patterns

The state of long-range order (LRO) and short-range order (SRO) in Ni4Mo has been a topic of interest for a considerable time (see Brooks et al.). The SRO is often referred to as 1½0 order from the apparent position of the diffuse maxima in diffraction patterns, which differs from the positions of the LRO (D1a) structure. Various studies have shown that a fully disordered state cannot be retained by quenching, as the atomic arrangements responsible for the 1½0 maxima are present at temperatures above the critical ordering temperature for LRO. Over 20 studies have attempted to identify the atomic arrangements associated with this state of order. A variety of models have been proposed, but no consensus has been reached. It has also been shown that 1 MeV electron irradiation at low temperatures (∼100 K) can produce the disordered phase in Ni4Mo. Transmission electron microscopy (TEM), atom probe field ion microscopy (APFIM), and electron irradiation disordering have been applied in the current study to further the understanding of the ordering processes in Ni4Mo.

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Measurements of the Zener Effect and Kinetics of Short-Range Order in Two AuCu Alloys (Containing 14 and 25 at% Cu)

physica status solidi (b) ◽

10.1002/pssb.19690310133 ◽

1969 ◽

Vol 31 (1) ◽

pp. 277-283 ◽

Cited By ~ 15

Author(s):

S. Radelaar ◽

J. M. J. Ritzen

Keyword(s):

Short Range ◽

Short Range Order ◽

Range Order ◽

Cu Alloys ◽

Kinetics Of

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Derelaxation of Amorphous Silicon by Ion Implantation: Optical Characterization

MRS Proceedings ◽

10.1557/proc-235-77 ◽

1991 ◽

Vol 235 ◽

Author(s):

R. Reitano ◽

M. G. Grimaldi ◽

P. Baeri ◽

E. Bellandi ◽

A. Borghesi ◽

...

Keyword(s):

Amorphous Silicon ◽

Short Range ◽

Short Range Order ◽

Structural Changes ◽

Low Dose ◽

Near Infrared ◽

Ion Irradiation ◽

Infrared Region ◽

Range Order ◽

Density Of State

ABSTRACTThe transition between relaxed and unrelaxed amorphous silicon can be obtained by thermal treatment of the unrelaxed amorphous or by low dose ion irradiation of the relaxed material. In both cases a variation in the short range order has been invoked to explain the behavior of the structural changes probed by various techniques. In this work we study the influence of such changes on the optical properties of a-Si in the region of the transition between the relaxed and the unrelaxed states. We show that a progressive variation of the optical constant in the visible-near infrared region upon derelaxation occurs. Therefore, significant modifications of the electron density of state in the region above the optical gap are associated with the changes in the short range order probed by Raman spectroscopy.

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