Random-anisotropy mixed-spin Ising on a triangular lattice

Abstract

We have studied the mixed spin-1/2 and 1 Ising ferrimagnetic system with a random anisotropy on a triangular lattice with three interpenetrating sublattices $A$, $B$, and $C$. The spins on the sublattices are represented by $\sigma_{A}$ (states $\pm1/2$), $\sigma_{B}$ (states $\pm1/2$), and $S_{C}$ (states $\pm1$, $0$). We have performed Monte Carlo simulations to obtain the phase diagram temperature $k_{\text{B}}T/\left|J\right|$ versus the strength of the random anisotropy $D/\left|J\right|$. The phase boundary between two ferrimagnetic $FR_{1}$ and $FR_{2}$ phases at lower temperatures are always first-order for $p<0.25$ and second-order phase transition between the $FR_{1}$, $FR_{2}$ and the paramagnetic $P$ phases. On the other hand, for values of $p\gtrapprox0.5$, the phase diagram presents only second-order phase transition lines.