Structure and Dynamics Group

The effects of a long-range interaction in a one-dimensional (1D) magnetic ring is studied. In this work, the Monte Carlo method is employed to obtain the equilibrium state of a modified quasi-1D Ising model having a dipolar interaction in a ring geometry. At low temperatures (T), the behavior of the magnetization (M) as a function of T is shown to depend on the strength of the dipolar interaction (G). For a ring consisting of 10 spins, ferromagnetic states occur in the ground state (T=0) for a small value of G. Antiferromagnetic states are favored when G is large even at a finite temperature. The magnetization saturates at high T. Also, an effective lowering of the total energy is achieved when smaller values of G approach zero and when large value of G is increased further. Similar effects are observed for rings having a larger number of spins.