Critical behavior of a triangular lattice Ising AF/FM bilayer

Abstract

We study a bilayer Ising spin system consisting of antiferromagnetic (AF) and ferromagnetic (FM) triangular planes, coupled by ferromagnetic exchange interaction, by standard Monte Carlo and parallel tempering methods. The AF/FM bilayer is found to display the critical behavior completely different from both the single FM and AF constituents as well as the FM/FM and AF/AF bilayers. Namely, by finite-size scaling (FSS) analysis we identify at the same temperature a standard Ising transition from the paramagnetic to FM state in the FM plane that induces a ferrimagnetic state with a finite net magnetic moment in the AF plane. At lower temperatures there is another phase transition, that takes place only in the AF plane, to different ferrimagnetic state with spins on two sublattices pointing parallel and on one sublattice antiparallel to the spins on the FM plane. FSS indicates that the corresponding critical exponents are close to the two-dimensional threestate ferromagnetic Potts model values.

Ordering phenomena in a heterostructure of frustrated and unfrustrated triangular-lattice Ising layers

“…This is a continuation of the previous investigation of the same model presented in Ref. 26, where J = 0.5 was assumed (i.e., −J A = J B = J AB ). We will also consider more general cases where J A and J B have different amplitudes, taking (J B , J AB ) = (0.4, 0.6) and (0.1, 0.9) with varying J A as our examples.…”

“…A prior account of such a bilayer system has been provided in Ref. 26, which pointed to the existence of the ferrimagnetic (FR) LRO phase also in the AF plane, induced by an effective field coming from the FM plane. In the present study we demonstrate that the competing ordering and disordering tendencies enforced by the respective unfrustrated and frustrated planes in the AF/FM bilayer result in a rather intricate critical and pseudocritical behaviors in the exchange interaction parameter space.…”

Road to zero-field antiferromagnetic skyrmions in a frustrated AFM/FM heterostructure

“…However, coupling of such either isotropic or anisotropic FM layer to another frustrated AFM layer makes the situation more involved in both layers. We note that critical properties of such a AFM/FM bilayer have already been studied for the special case of A → ∞ (Ising model) [26,27]. In the present AFM/FM bilayer system we can observe that the FM LRO starts forming in the FM layer at finite A, however, not at very low temperatures but only within some range of intermediate values (see the green curve in Fig.…”

Efectos de anisotropía de ion simple sobre un sistema ferrimagnético de espines enteros

“…En el caso que nos compete estudiaremos un ferrimagneto tipo Ising mixto de espines 𝑆 = 1 y 𝜎 = 2 estructurado en una red cuadrada. Cabe destacar que los modelos de Ising mixtos han probado ser de gran utilidad en la caracterización magnética de los complejos materiales magnéticos (De La Espriella, 2016;Žukovič and Bobák, 2016; Karimou and Bati, 2021), dado que se han obtenido interesantes resultados acerca de fenómenos críticos como comportamientos reentrantes, doblemente reentrantes y transiciones discontinuas (Magoussi et al, 2013;Temizer et al, 2016;De La Espriella et al, 2017), entre otros, en diversas redes cristalinas entre los que se destacan óxidos ferrimagnéticos amorfos con iones de Fe 3+ (Htoutou et al, 2004).…”