On the energy spectrum and thermodynamics of decorated quasi-one-dimensional magnetic systems with uniaxial anisotropy

Abstract

This paper is devoted to the study of thermodynamics of the quasi-1D spin models with Ising interaction between complex unit cells by transfer-matrix method. The field and the temperature dependences of the main thermodynamic characteristics have been investigated. It is shown that the field dependence of the magnetization at low temperatures for the models of “comb” and “decorated comb,” and decorated triangles structures have an intermediate magnetization plateau in case of antiferromagnetic Ising interactions. The temperature dependence of the heat capacity may have several maxima in zero magnetic field. For the chain model of triangles decorated by Ising spins through the one vertex and for the “double decorated comb” some kind of the pseudo-phase transitions in the critical magnetic field is found.