Tuesday, October 18, 2011
Exhibit Hall B (Minneapolis Convention Center)
We have carried out Monte Carlo simulations in order to investigate influences of external magnetic and gravity fields on the self-assembled lattice structures of a monolayer composed of cubic hematite particles. We emploied the hematite particle model which is a cubic rigid body, and has a magnetic moment along to the diagonal direction at the particle center. The energies of interaction between particle and both the magnetic and in-plane gravity fields, and also the energy of magnetic dipole-dipole interaction are taken into account in the simulation. The obtained results are summarized as follows: Particles are integrated near the bottom wall and form ordered lattice structures under relatively weak gravity field. For an uniform magnetic field is applied in an opposite direction of the gravity field, oblique and square lattice structures can be formed depending on the barnce between energies of the magnetic and gravity fields. For the magnetic field direction along to the upper-right (45° from the x-axis), well-ordered oblique lattice structures are formed and they have different lattice constant from the first-mentioned oblique lattice for the magnetic field along the y-axis direction. It suggest that relative angle between the magnetic and the gravity fields is also important for the lattice structures.