Long: Magnetic Recording and Kagome.

Short: Magnetic Recording and Kagome.

The study of systems with competing interactions often reveals exotic magnetic states, phase transitions and phase diagrams. Strong antiferromagnetic exchange forces which cannot be fully satisfied due to geometrical constraints imposed by certain crystal symmetries (e.g., triangular) provide a rich variety of new phenomena realized in a number of large classes of real magnetic materials. Much weaker and long-ranged ferromagnetic dipole interactions can then be important in breaking otherwise degenerate states of such frustrated systems.
Systems with strong ferromagnetic exchange interactions can also experience geometrical frustration in nanometer size thin films. The much weaker but more long-range dipole forces are strongly influenced by sample geometry and a large number of magnetic configurations can occur. Investigations by numerical techniques of such systems provides a challenge due to the long-range nature of dipole forces as well as the large number of nearly degenerates states which are possible.
Micromagnetics is a particular formalism (the Landau-Lifshitz-Gilbert equations) developed to study static and dynamical behavior of thin ferromagnetic films and has not been widely applied to other systems. For systems which exhibit phase transitions, much understanding is available through analytic techniques provided by development and analysis of an appropriate Landau free energy. Critical phenomena associated with these transitions can often be investigated using simple numerical Monte Carlo techniques.


Martin Plumer
Department of Physics and Physical Oceanography
Memorial University of Newfoundland
St. John's, NL
A1B 3X7
Canada
email: plumer@mun.ca