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Field‐induced phase transitions in a randomly diluted antiferromagnet. Mean‐field description of classical spin model
Author(s) -
Moreira F. G. Brady,
Fittipaldi I. P.,
Rezende S. M.,
TahirKheli R. A.,
Žekš B.
Publication year - 1977
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.2220800145
Subject(s) - condensed matter physics , antiferromagnetism , phase diagram , anisotropy , spins , mean field theory , spin (aerodynamics) , dilution , dipole , physics , crystal (programming language) , magnetic anisotropy , field (mathematics) , paramagnetism , phase (matter) , magnetization , magnetic field , quantum mechanics , thermodynamics , mathematics , computer science , pure mathematics , programming language
Within a mean‐field virtual crystal approximation, a phase diagram is given in the H – T plane of a randomly diluted, uniaxial Heisenberg antiferromagnet with classical spins and single ion anisotropy. The temperature dependence of the critical fields, separating the antiferromagnet (af), the spin‐flop (sf), and the paramagnetic (pm) phases are analyzed as a function of the dilution. For systems where the anisotropy is of crystal‐field origin and where the non‐magnetic impurity does not perturb the crystal field, the phase boundaries show an interesting dependence on the dilution. On the other hand, in systems such as (Mn) x (Zn) 1‐ x F 2 , where the anisotropy is due to two particle interactions, such as dipolar forces, the present theory would predict only a linear scaling of the phase diagram with magnetic dilution. Thus, the study of magnetically diluted systems would seem to offer a possible method of characterizing the anisotropy.