Physical Review E
We use Monte Carlo and transfer matrix methods in combination with extrapolation schemes to determine the phase diagram of the two-dimensional superantiferromagnetic (SAF) Ising model with next-nearest-neighbor (NNN) interactions in a magnetic field. The interactions between nearest-neighbor (NN) spins are ferromagnetic along x, and antiferromagnetic along Y. We find that for sufficiently low temperatures and fields, there exists a region limited by a critical line of second-order transitions separating a SAF phase from a magnetically induced paramagnetic phase. We did not find any region with either first-order transition or with reentrant behavior. The NNN couplings produce either an expansion or a contraction of the SAF phase. Expansion occurs when the interactions are antiferromagnetic, and contraction when they are ferromagnetic. There is a critical ratio Rc=½ between NNN and NN couplings, beyond which the SAF phase no longer exists.
Algorithms; Magnetic Fields; Models, Statistical; Phase Transition
Citation: Pilot Scholars Version (Modified MLA Style)
Saguia, A.; Boechat, B.; Florencio, J.; and Bonfim, O. F. de Alcantara, "Phase transitions in the two-dimensional superantiferromagnetic Ising model with next-nearest-neighbor interactions" (2013). Physics Faculty Publications and Presentations. Paper 52.