Quantum anisotropic antiferromagnetic Heisenberg model for description of magnetic properties at low temperatures from KTb(WO4)2

Abstract

Low dimensional magnetic systems have attracted the attention of several researchers in recentdecades, mainly because from exotic magnetic properties and the superconductivity that, in someof these systems, occur as result from characteristics of such materials. One of these materialsis KTb(WO4)2, generally considered a prototype from 2D Ising model, but which presents somepeculiarities on the magnetization diagram at low temperatures, especially the non-linear dependenceof magnetization with the applied magnetic field, behavior that cannot be described via puretwo-dimensional Ising model. The system presents structural and metamagnetic phase transition atlow temperatures, and we believe that such behavior may be related quantum effects and despitepresenting high anisotropy, this material it would not be a perfect prototype of the Ising model intwo dimensions. In this work, we present a proposal for using the anisotropic quantum Heisenbergmodel for describing the magnetic properties of the KTb(WO4)2 quasi-doublet with the objective,mainly, to describe non-linear properties at low temperatures. To achieve our goal, we simulatedthe magnetic properties of the material considering several anisotropy values via Quantum MonteCarlo (QMC) and compared the results with experimental data available already published. Tocomparison, we obtained diagrams of magnetization versus field and susceptibility dependence oftemperature (low temperature regime). Our results show excellent agreement with the experimentaldata, especially at low temperatures and for intermediate values from magnetic anisotropy.