About this Journal Submit a Manuscript Table of Contents
ISRN Thermodynamics
Volume 2012 (2012), Article ID 917836, 11 pages
http://dx.doi.org/10.5402/2012/917836
Research Article

Thermodynamics of f.c.c.-Ni–Fe Alloys in a Static Applied Magnetic Field

1Department of Theoretical Physics, Institute for Applied Physics, N.A.S. of Ukraine, 58 Petropavlivska Street, 40030 Sumy, Ukraine
2Department of Solid State Theory, G. V. Kurdyumov Institute for Metal Physics, N.A.S. of Ukraine, 36 Academician Vernadsky Boulevard, 03680 Kyyiv-142, Ukraine
3Department of Materials Design and Technology, Institute for Advanced Materials Science and Innovative Technologies, 15 Sauletekio Avenue, 10224 Vilnius, Lithuania
4Department of Partial Differential Equations, Laboratoire Jean Kuntzmann, UMR 5224 CNRS, Tour IRMA, rue des Mathématiques 51, P.O. Box 53, 38041 Grenoble Cedex 9, France

Received 10 February 2012; Accepted 27 February 2012

Academic Editors: N. S. Ananikian, G. Maurin, B. Merinov, and S. Yulin

Copyright © 2012 I. V. Vernyhora et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Within the scope of the self-consistent field and mean (‘‘molecular’’) self-consistent field approximations, applying the static concentration wave method, the thermodynamics of f.c.c.-Ni–Fe alloys undergoing the static applied magnetic field effects is studied in detail. Under such conditions, the analytical corrections to expressions for the configuration-dependent part of free energy of macroscopically ferromagnetic L12-Ni3Fe-type or L10-NiFe-type ordering phases are taken into account. The obtained results for thermodynamically equilibrium states are compared with the refined phase diagram for f.c.c.-Ni–Fe alloys calculated recently without taking into account the applied magnetic field effects. Considering the specific character of microscopic structure of the magnetic and atomic orders in f.c.c.-Ni–Fe alloys, the changes of shape (and in arrangement) of order-disorder phase-transformation curves (Kurnakov points) are thoroughly analysed. A special attention is addressed to the investigation of the concentration, temperature, and magnetic-field induction-dependent atomic and magnetic long-range order parameters, especially, near their critical points. As revealed unambiguously, influence of a static applied magnetic field promotes the elevation of Kurnakov points for all the atomically ordering phases that is in an overall agreement with reliable experimental data. On the base of revealed phenomenon, the magneto external field analog-to-digital converter of the monochromatic radiations (X-rays or thermal neutrons) is hypothesized as a claim.