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

Abstract

We study critical and magnetic properties of a bilayer Ising system consisting of two triangular planes A and B, with the antiferromagnetic (AF) coupling $J_{\mathrm{A}}$ and the ferromagnetic (FM) one $J_{\mathrm{B}}$ for the respective layers, which are coupled by the interlayer interaction $J_{\mathrm{AB}}$ by using Monte Carlo simulations. When $J_{\mathrm{A}}$ and $J_{\mathrm{B}}$ are of the same order, the unfrustrated FM plane orders first at a high temperature $T_{c1}\sim J_{\mathrm{B}}$. The spontaneous FM order then exerts influence on the other frustrated AF plane as an effective magnetic field, which subsequently induces a ferrimagnetic order in this plane at low temperatures below $T_{c2}$. When short-range order is developed in the AF plane while the influence of the FM plane is still small, there appears a preemptive Berezinskii-Kosterlitz-Thouless-like pseudocritical crossover regime just above the ferrimagnetic phase transition point, where the short-distance behavior up to a rather large length scale exponentially diverging in $\propto \JA / T$ is controlled by a line of Gaussian fixed points at $T=0$. In the crossover region, a continuous variation in the effective critical exponent $4/9\lesssim {\eta }^{\mathrm{eff}}\lesssim 1/2$ is observed. The phase diagram by changing the ratio $J_{\mathrm{A}}/J_{\mathrm{B}}$ is also investigated.

13 pages, 16 figures

References in corpus (5)

• The influence of interplanar coupling on the entropy and specific heat of the bilayer ferromagnet
• Critical Temperature Studies of the Anisotropic Bi- and Multilayer Heisenberg Ferromagnets in Pair Approximation
• Critical behavior of a triangular lattice Ising AF/FM bilayer
• Stiffness from Disorder in Triangular-Lattice Ising Thin Films
• Monomer-Dimer Mixture on a Honeycomb Lattice

Cited by in corpus (1)

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