Phase transitions of the mixed spin-1/2 and spin-S Ising model on a three-dimensional decorated lattice with a layered structure

TL;DR

This study explores phase transitions in a layered 3D mixed spin-1/2 and spin-S Ising model, revealing how critical behavior depends on interaction strengths and zero-field splitting, with implications for quasi-1D magnetic systems.

Contribution

It provides a novel exact mapping of the 3D layered mixed-spin Ising model to a simpler 2D model, enabling detailed analysis of phase transitions and critical behavior.

Findings

Critical behavior depends on interaction parameters and zero-field splitting.

Spontaneous order occurs in a restricted parameter region with non-magnetic spin states.

Mapping approach allows precise analysis of complex layered magnetic systems.

Abstract

Phase transitions of the mixed spin-1/2 and spin-S (S >= 1/2) Ising model on a three-dimensional (3D) decorated lattice with a layered magnetic structure are investigated within the framework of a precise mapping relationship to the simple spin-1/2 Ising model on the tetragonal lattice. This mapping correspondence yields for the layered Ising model of mixed spins plausible results either by adopting the conjectured solution for the spin-1/2 Ising model on the orthorhombic lattice [Z.-D. Zhang, Philos. Mag. 87 (2007) 5309-5419] or by performing extensive Monte Carlo simulations for the corresponding spin-1/2 Ising model on the tetragonal lattice. It is shown that the critical behaviour markedly depends on a relative strength of axial zero-field splitting parameter, inter- and intra-layer interactions. The striking spontaneous order captured to the 'quasi-1D' spin system is found in a restricted region of interaction parameters, where the zero-field splitting parameter forces all integer-valued decorating spins towards their 'non-magnetic' spin state.