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Spin wave dispersion and energy bands in fcc metals
Author(s) -
Thompson Eric D.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560010665
Subject(s) - brillouin zone , dispersion (optics) , condensed matter physics , spin wave , chemistry , excited state , exchange interaction , spin (aerodynamics) , energy level splitting , atom (system on chip) , dispersion relation , atomic physics , physics , ferromagnetism , quantum mechanics , computer science , thermodynamics , embedded system
The spin wave dispersion along the principal axis directions from the center to the surface of the Brillouin zone is studied numerically for the fee metals, the study being based on the 3 d energy bands of nickel as calculated by Hanus. The dispersion dependence on the splitting between the up‐ and down‐spin bands and on the magnitude of the interatomic exchange is given. Fourier analysis of the dispersion curves indicates that an effective exchange interaction is long range. It is also found that for sufficiently large interatomic exchange, the spin wave spectrum intersects the continuum of single particle excitations and that the single particle excitations will be thermally excited at temperatures well below the Curie point. Using experimental spin wave mass values for the nickel‐copper alloys, the results of this dispersion calculation indicate that the splitting between the up‐ and down‐spin bands decreases more rapidly with increasing copper than does the effective number of Bohr magnetons per atom. This implies that the effective band splitting interaction is alloy dependent.