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Spin waves in a semi‐infinite field‐induced metamagnet with three‐ion anisotropic interactions. I. Green function approach
Author(s) -
Rudziński W.,
Maciejewski W.
Publication year - 1992
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221740224
Subject(s) - condensed matter physics , anisotropy , antiferromagnetism , spin wave , spin (aerodynamics) , quartic function , field (mathematics) , physics , spin structure , ion , materials science , quantum mechanics , thermodynamics , mathematics , ferromagnetism , pure mathematics
A quartic spin model with three‐ion anisotropic interactions is employed to study surface and bulk spin waves in a layered structure of a semi‐infinite field‐induced metamagnet with a (001) surface at low temperatures, T ≪ T N . The three‐ion surface anisotropy field is allowed to deviate from the bulk value. The calculations involve a derivation of expressions for the spin‐spin Green functions for the semi‐infinite medium. The Green functions are found to have poles at energies corresponding to bulk and surface spin‐wave modes. The theory includes an evolution of the dispersion relations for both the antiferromagnetic and paramagnetic phases.