Study of planar lattice of magnetic particles

We study small identical magnetic particles embedded in a non-magnetic medium with their centers lying in a two-dimensional regular lattice. Within the approximation of the Weiss molecular field due to the magnetic dipole moments of the neighboring particles on the spins of a central particle, we derive general expressions for magnetization and magnetic susceptibility of the system. As an application, we discuss the ordering for a square lattice.© Elsevie

On the Coulomb interaction in carbon onions and their absorption spectra

We have previously demonstrated the existence of a rich spectrum of collective resonances for both carbon tubes and carbon onions using a classical electrodynamic model. Collective resonances in these systems are predicted to dominate their respective UV spectra. In this study we present results which demonstrate how the coupling between the shells via the Coulomb interaction completely determines the absorption cross section. The outermost shells are strongly screened for low frequencies and frequencies close to the effective plasma frequency of the shells