5 research outputs found
Forces between elongated particles in a nematic colloid
Using molecular dynamics simulations we study the interactions between elongated colloidal particles (length to breath ratio ≫1) in a nematic host. The simulation results are compared to the results of a Landau–de Gennes elastic free energy. We find that depletion forces dominate for the sizes of the colloidal particles studied. The tangential component of the force, however, allows us to resolve the elastic contribution to the total interaction. We find that this contribution differs from the quadrupolar interaction predicted at large separations. The difference is due to the presence of nonlinear effects, namely, the change in the positions and structure of the defects and their annihilation at small separations
Defect structures and torque on an elongated colloidal particle immersed in a liquid crystal host
Combining molecular dynamics and Monte Carlo simulation we study defect
structures around an elongated colloidal particle embedded in a nematic liquid
crystal host. By studying nematic ordering near the particle and the
disclination core region we are able to examine the defect core structure and
the difference between two simulation techniques. In addition, we also study
the torque on a particle tilted with respect to the director, and modification
of this torque when the particle is close to the cell wall
Inhomogeneous States in a Small Magnetic Disk with Single-Ion Surface Anisotropy
We investigate analytically and numerically the ground and metastable states
for easy-plane Heisenberg magnets with single-ion surface anisotropy and disk
geometry. The configurations with two half-vortices at the opposite points of
the border are shown to be preferable for strong anisotropy. We propose a
simple analytical description of the spin configurations for all values of a
surface anisotropy. The effects of lattice pinning leads to appearance of a set
of metastable configurations.Comment: 10 pages, 7 figures; submitted to Phys. Rev.
Weak anchoring effects in ferronematic systems
We study the magnetically induced behaviour of a ferronematic cell with finite anchoring energy at the cell surfaces. We calculate the dependence of orientational and concentration profiles on the magnetic field, the director anchoring energy, and the cell thickness. We find a new intermediate thickness high field state, in which there is no ferroparticle segregation and a highly ordered director field. This contrasts with previous work in which only a restricted set of system parameters and strong anchoring at the cell surfaces were considered