Long-range order and the β −βʹ transition in single crystal V2H via X-ray scattering

ABSTRACTWe have carried out x-ray scattering studies in melts of a series of linear polyisoprenes with highly polar sulfo-zwitterion groups at one end. The zwitterion end groups cause aggregation in good solvents for polyisoprene. The aggregation number depends strongly on the molecular weight of the polyisoprene tails and on the polarity of the solvent. Molecular mechanics simulations of the interactions between the zwitterion head groups suggest tubelike or diskline structures for the aggregates. Spherical structures are not energetically favorable. High resolution synchrotron x-ray scattering studies were carried out for six different (chain) molecular weights between 2000 and 23,000. For low molecular weights (between 2000 and 4000) a tubular structure is found with the tubes organized on a well-defined, two-dimensional triangular lattice with very large domain sizes >2000Å. A structural phase transition to a cubic (bcc) phase with long range order is observed to occur for molecular weights >10,000. The lattice spacing increase over the molecular range was between 95Å (for MW-2000) and 206Å (for MW-23,000). For the high molecular weight melts, annealing transforms the structure from (bcc) (with long range order) to an (fcc) disordered structure with short range order.

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Long-range order and short-range order study on CoCrPt/Ti films by synchrotron x-ray scattering and extended x-ray absorption fine structure spectroscopy

Journal of Applied Physics ◽

10.1063/1.1448799 ◽

2002 ◽

Vol 91 (10) ◽

pp. 7182 ◽

Cited By ~ 11

Author(s):

C. J. Sun ◽

G. M. Chow ◽

J. P. Wang ◽

E. W. Soo ◽

Y. K. Hwu ◽

...

Keyword(s):

Fine Structure ◽

Long Range ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Long Range Order ◽

X Ray ◽

X Ray Scattering ◽

X Ray Absorption ◽

Ti Films

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Single crystal X-ray study of the superstructure modulation and long-range order in V2D

phys stat sol (a) ◽

10.1002/pssa.2210470234 ◽

1978 ◽

Vol 47 (2) ◽

pp. 631-638 ◽

Cited By ~ 20

Author(s):

H. Metzger ◽

H. Jo ◽

S. C. Moss ◽

D. G. Westlake

Keyword(s):

Single Crystal ◽

Long Range ◽

Range Order ◽

Long Range Order ◽

X Ray

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Short-range order and diffuse X-ray scattering in single crystal PbxSn1−xTe alloys

phys stat sol (a) ◽

10.1002/pssa.2210340214 ◽

1976 ◽

Vol 34 (2) ◽

pp. 525-531 ◽

Cited By ~ 2

Author(s):

C. Ghezzi

Keyword(s):

Single Crystal ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

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Time-Resolved X-ray Scattering Investigation of Ordering Kinetics in Fe3Ai

MRS Proceedings ◽

10.1557/proc-205-119 ◽

1990 ◽

Vol 205 ◽

Cited By ~ 6

Author(s):

B. Park ◽

G. B. Stephenson ◽

K. F. Ludwig ◽

S. M. Allen

Keyword(s):

Long Range ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Long Range Order ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Disordered Phase ◽

Kinetics Of

AbstractWe have investigated the kinetics of the B2/DO3 transition in Fe3AI (28 at. %) using in situ time-resolved x-ray scattering. In these experiments, the evolution of the diffuse and/or Bragg intensity near the (½ ½ ½) DO3 superlattice peak is observed after the temperature of the sample is abruptly changed. H-ere we present results for the kinetics of re-equilibration of short-range order within the disordered (B2) phase, and of short- and long-range order within the ordered (DO3) phase. The short-range order is characterized by the diffuse peak intensity IDIFFUSE and correlation length ξ;the long-range order is characterized by the Bragg intensity IBRAGG. For quenches within the disordered phase, IDIFFUSE and ξ both relax exponentially at the same rate. The temperature dependence of the relaxation time shows evidence of a divergence at the critical temperature. For shallow quenches within the ordered phase, IBRAGG, IDIFFUSE and ξ all relax exponentially, but with different rates. However, for deep quenches within the ordered phase, IDIFFUSE and ξ do not show simple exponential relaxation. Instead, coarsening of short-range order into long-range order is seen, as in quenches from the disordered phase into the ordered phase. Investigation of up-quenches and down-quenches to the same temperature within the ordered phase indicates that disordering is faster than ordering.

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