Onset of long-range order in superlattices: Mean-field theory

1992 ◽  
Vol 46 (18) ◽  
pp. 11681-11687 ◽  
Author(s):  
R. W. Wang ◽  
D. L. Mills
1987 ◽  
Vol 58 (21) ◽  
pp. 2245-2248 ◽  
Author(s):  
F. Solal ◽  
R. Caudron ◽  
F. Ducastelle ◽  
A. Finel ◽  
A. Loiseau

1990 ◽  
Vol 213 ◽  
Author(s):  
C. J. Sparks ◽  
E. D. Specht ◽  
G. E. Ice ◽  
P. Zschack ◽  
J. Schneibel

ABSTRACTThe degree of long-range order in the trialuminides is determined by X-ray powder diffraction techniques. Long-range order exists to their melting points. For the binary trialuminides Al3Ti, Al73Ti27, and Al3Sc, the degree of long-range order is nearly perfect and is a measure of the lack of mixing of the aluminum atoms onto the sublattice occupied by either Ti or Sc. A calculation of the bond energy between neighboring pairs of atoms from the ordering (melting) temperature is made following the Bragg-Williams mean field theory approach. These bond energies compare favorably with more sophisticated calculations. Bond energies are found to be larger than the energy difference between the crystal structure forms DO22, Ll2, and DO23, and therefore, more relevant to understanding the mechanical and chemical behavior of the trialuminides. Ordering or melting temperatures of these intermetallics reflect the strong Al-metal near-neighbor pair potentials and may provide insights to their brittle properties.


2000 ◽  
Vol 61 (17) ◽  
pp. 11521-11528 ◽  
Author(s):  
Sergio A. Cannas ◽  
A. C. N. de Magalhães ◽  
Francisco A. Tamarit

1993 ◽  
Vol 07 (29n30) ◽  
pp. 1947-1950 ◽  
Author(s):  
RAFFAELLA BURIONI ◽  
DAVIDE CASSI

We rigorously prove that the correlation functions of any statistical model having a compact transitive symmetry group and nearest-neighbor interactions on any tree structure are equal to the corresponding ones on a linear chain. The exponential decay of the latter implies the absence of long-range order on any tree. On the other hand, for trees with exponential growth such as Bethe lattices, one can show the existence of a particular kind of mean field phase transition without long-range order.


2015 ◽  
Vol 92 (3) ◽  
Author(s):  
T. B. Pedro ◽  
W. Figueiredo ◽  
A. L. Ferreira

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