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A Green's function investigation of nearly two‐dimensional and nearly one‐dimensional Heisenberg ferromagnets
Author(s) -
Treplin W.,
Jelitto R. J.
Publication year - 1978
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.2220900114
Subject(s) - decoupling (probability) , heisenberg model , ferromagnetism , statistical physics , physics , assertion , theoretical physics , condensed matter physics , computer science , engineering , control engineering , programming language
A Heisenberg model of a ferromagnet is considered, which is modified such that one can change continuously from three to two and to one dimensions. The thermodynamic properties of this model are evaluated by application of Green's functions. A special decoupling procedure is needed in order to provide a Stanley transition for the two‐dimensional model. The results of the theory are evaluated both asymptotically and numerically. By these results an assertion drawn from a former paper is substantiated in so far, that already a tiny interaction between different two‐dimensional magnetic layers is sufficient for producing essentially three‐dimensional magnetic behaviour. By consideration of the various nearest neighbour spin correlations one gets some insight into the question of the reliability of the applied decoupling scheme.