Efeito magnetocalórico em compostos semelhantes a Cu3 usando o modelo antiferromagnético de Heisenberg em uma estrutura triangular

Abstract

In this work we present a theoretical investigation into an antiferromagnetically coupled spin system, specifically Cu3 −X (X = As, Sb), which exhibits an isosceles triangular configuration or slightly distorted equilateral triangular configuration, as previously identified in reference (CHOI et al., 2006). This system can be effectively represented by the Heisenberg model on a triangular structure, taking into account the exchange interaction, the Dzyaloshinskii-Moriya interaction, g-factors and external magnetic field, as delineated in the aforementioned refe- rence. By using numerical approach we explore both zero-temperature and finite-temperature behaviors of a Cu3-like antiferromagnetically coupled spin system. At zero temperature, the system displays a 1/3 quasi-plateau magnetization, when the magnetic field is varied. More- over, we place particular emphasis on magnetic properties including magnetization, magnetic susceptibility, entropy, and specific heat at finite temperatures. Furthermore, we investigate the magnetocaloric effect as a function of an externally imposed magnetic field, oriented both parallel and perpendicular to the plane of the triangular structure. Interestingly, these configura- tions demonstrate remarkably similar behavior for both orientations of the magnetic field. Our investigation also includes an analysis of the adiabatic curve, the Grüneisen parameter, and the variation in entropy when applied or removed the magnetic field. The magnetocaloric effect is found to be more prominent at low temperature region (below T ∼ 1K) and at ∼ 4.5T and ∼ 5T for parallel and perpendicular magnetic fields, respectively.