Electronic structure and ferromagnetic effect in Ni 2 MnGa alloy
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Fig. 5—Model predictions of the dependence of the fractional increase in particle size as a function of normalized particle radius. 262—VOLUME 36A, JANUARY 2005
This work was conducted as part of the in-house research of the Metals Processing Group, Air Force Research Laboratory’s Materials and Manufacturing Directorate. The support of the laboratory management and the Air Force Office of Scientific Research (Dr. C.S. Hartley, program manager) is gratefully acknowledged. This project was motivated by the Air Force Metals Affordability Initiative program on Microstructure and Mechanical Property Modeling for Wrought Titanium Alloys led by Ladish Company (Cudahy, WI). One of the authors (JDM) was supported under the auspices of Contract No. F33615-03-D-5801. REFERENCES 1. S.V. Zherebstov, G.A. Salishchev, R.M. Galeyev, O.R. Valiakhmetov, and S.L. Semiatin: Proc. 2nd Int. Conf. on Nanomaterials by Severe Plastic Deformation: Fundamentals–Processing–Applications, M.J. Zehetbauer and R.Z. Valiev, eds., Wiley-VCH, Weinheim, Germany, 2004, pp. 835-40. 2. R.R. Boyer and D.U. Furrer: The Potential Advantages of Microstructure Modeling of Titanium to the Aerospace Industry, in NUMIFORM 2004, S. Ghosh, J.M. Castro, and J.K. Lee, eds., American Institute of Physics, Melville, NY, 2004, pp. 1694-99. 3. S.L. Semiatin, B.C. Kirby, and G.A. Salishchev: Metall. Mater. Trans. A, 2004, vol. 35A, pp. 2809-19. 4. S.L. Semiatin, S.L. Knisley, P.N. Fagin, F. Zhang, and D.R. Barker: Metall. Mater. Trans. A, 2003, vol. 34A, pp. 2377-86. 5. H.S. Carslaw and J.C. Jaeger: Conduction of Heat in Solids, Oxford University Press, London, 1959. 6. W.P. Bosze and R. Trivedi: Metall. Trans., 1974, vol. 5, pp. 511-12.
Electronic Structure and Ferromagnetic Effect in Ni2MnGa Alloy J.F. WAN, X.L. LEI, S.P. CHEN, and T.Y. HSU By using the first-principles discrete variational method (DVM), we have investigated the magnetic contribution to the binding energy, the Fermi energy level, the interatomic energy, the bond order (BO), the total density of states (DOS), and the charge density distribution for varying c/a in Ni2MnGa alloy. The binding energy curves for the ferromagnetic (FM) phase for varying c/a are more complicated than those in the nonferromagnetic (NM) phase whose energy difference displays the magnetic contribution to the binding of the crystal. The interactions between the central atom Mn and the surrounding atoms, including the interatomic energies and the BOs, are different from each other, which leads to crystal anisotropy. The finding suggests that the interatomic energy difference between the FM and NM phases will be the origin of magnetic anisotropy. The difference in electron density on the different distortions for the FM and NM phases varying with c/a shows the different redistribution of the magnetization for the Mn and Ni in the [110] plane.
J.F. WAN, Lecturer, S.P. CHEN and T.Y. HSU, Professors, are with the School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, P.R. China. Contact e-mail: j
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