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Exact results of the mixed-spin Ising model on a decorated square lattice with two different decorating spins of integer magnitudes

Lucia Canova·Jozef Strecka·Michal Jascur
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Abstract

The mixed-spin Ising model on a decorated square lattice with two different decorating spins of the integer magnitudes S_B = 1 and S_C = 2 placed on horizontal and vertical bonds of the lattice, respectively, is examined within an exact analytical approach based on the generalized decoration-iteration mapping transformation. Besides the ground-state analysis, finite-temperature properties of the system are also investigated in detail. The most interesting numerical result to emerge from our study relates to a striking critical behaviour of the spontaneously ordered 'quasi-1D' spin system. It was found that this quite remarkable spontaneous order arises when one sub-lattice of the decorating spins (either S_B or S_C) tends towards their 'non-magnetic' spin state S = 0 and the system becomes disordered only upon further single-ion anisotropy strengthening. The effect of single-ion anisotropy upon the temperature dependence of the total and sub-lattice magnetization is also particularly investigated.

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Lucia Canova, Jozef Strecka, Michal Jascur. 2007-05-16. Exact results of the mixed-spin Ising model on a decorated square lattice with two different decorating spins of integer magnitudes. https://doi.org/10.1142/s0217979208039526

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