Diffuse Scattering of Neutrons in Ni3V and Pt3 V: Test of the Gamma Expansion Method Approximation in a Degenerate Case
Our results of in situ diffuse scattering of neutrons in Ni3V and Pt3V are presented. In the Ising model framework, effective pair interactions (EPI) up to the 9th neighbor were extracted from the data. These EPI were used to explain successfully the transition temperature of both compounds, the core structure of the dislocations in Ni3V, and the occurrence of long periods in Pt3V. The need of approximations yielding long-range EPI is stressed. We give a description of the Gamma Expansion Method (GEM). Because of its mean field nature, we expected the GEM to fail in the highly degenerate case of Pt3V. We tested it in that case, and found it completely successful. This gives more confidence in the mean field approximations.
KeywordsMonte Carlo Spherical Model Diffuse Intensity Random Phase Approximation Diffuse Scattering
Unable to display preview. Download preview PDF.
- 1.F. Ducastelle, Order and Phase Stability in Alloys, edited by F. R. de Boer and D. G. Pettifor, Cohesion and Structure Vol. 3 (North-Holland, Amsterdam, 1991).Google Scholar
- 3.F. Solal, R. Caudron, and A. Finel, in Alloy Phase Stability, edited by G. M. Stocks and A. Gonis, NATO ASI series, series E: applied sciences, (Kluwer Acad. Publ., 1989), Vol. 163, p. 107.Google Scholar
- 4.A. Finel, M. Barrachin, R. Caudron, and A. François in Metallic alloys, Experimental and Theoretical Perspectives, edited by J. S. Faulkner and R. G. Jordan, Nato ASI series, series E: applied sciences, (Kluwer Acad. Publ., 1994), Vol. 256, p. 215.Google Scholar
- 8.R. Caudron, M. Sarfati, M. Barrachin, A. Finel, F. Ducastelle, and F. Solal, J. Phys. 12, 1145 (1992).Google Scholar
- 9.J. C. Sparks and B. Borie, in Local Atomic Arrangements studied by X-Ray Diffraction, edited by J. B. Cohen and J. E. Hilliard (Gordon and Breach, 1966).Google Scholar
- 10.C. L. Lawson and R. J. Hanson, Solving Linear Least Squares Problem, (Prentice- Hall, Englewood-Cliffs, New-Jersey, 1974).Google Scholar
- 11.A. Finel, Ph.D. thesis, Paris VI, 1987.Google Scholar
- 12.M. Barrachin, Ph.D. thesis, Paris XI-Orsay, 1993.Google Scholar
- 15.A. François, Ph.D. thesis, Paris VI, 1992.Google Scholar
- 16.E. Cabet and A. Loiseau, J. Phys. (France) IV colloque C7, Supp. III 3, 2051 (1993).Google Scholar
- 19.M. A. Krivoglaz, Theory of X-Rays and Thermal Neutron scattering by Real Crystals, (Plenum, New York, 1969).Google Scholar
- 20.R. H. Brout, Phase Transitions, (Benjamin, New York, 1965).Google Scholar