The stability of quasi 2D lattices of magnetic holes

Publisher Website
Google Scholar
Abstract
It has recently been demonstrated by Skjeltorp (1983, 1984) that a monolayer of non-magnetic inclusions in a paramagnetic fluid crystallises when a perpendicular magnetic field is applied. Temperature is scaled by this field and 2D melting has been observed. Here the authors examine the energetics of the stability of the regular structures formed. Competing dipolar interactions and a frustration under distortions give a range of possibilities including a strictly 2D triangular lattice, a quasi 2D distorted triangular lattice and a quasi 2D square lattice. A second melting possibility becomes evident, but they restrict the analysis of the interactions to zero temperature. The underlying lattice energies are all close and the delicacy involved in calculating their energies, arising from the long-range character of the forces involved, requires a modification of the Ewald technique. They perform a stability analysis to find instability modes and their amplitudes.