Title: The effect of uniaxial crystal-field anisotropy on magnetic properties of the superexchange antiferromagnetic Ising model
Author(s):

	L.Canová (Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J.Safárik University, Park Angelinum 9, 041 54 Kosice, Slovak Republic) ,
	M.Jascur (Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J.Safárik University, Park Angelinum 9, 041 54 Kosice, Slovak Republic)

The generalized Fisher super-exchange antiferromagnetic model with uniaxial crystal-field anisotropy is exactly investigated using an extended mapping technique. An exact relation between partition function of the studied system and that of the standard zero-field spin-1/2 Ising model on the corresponding lattice is obtained applying the decoration-iteration transformation. Consequently, exact results for all physical quantities are derived for arbitrary spin values S of decorating atoms. Particular attention is paid to the investigation of the effect of crystal-field anisotropy and external longitudinal magnetic field on magnetic properties of the system under investigation. The most interesting numerical results for ground-state and finite-temperature phase diagrams, thermal dependences of the sublattice magnetization and other thermodynamic quantities are discussed.

Key words: Fisher model, superexchange, uniaxial crystal-field anisotropy, decoration-iteration transformation, exact results
PACS: 05.50.+q, 05.70.Jk, 75.10.Dg, 75.50.Ee