Analysis of Self-assembly Lattice Structures Composed of Cubic Hematite Particles

作者：Aoshima Masayuki^*; Ozaki Masataka; Satoh Akira

来源：Kagaku Kogaku Ronbunshu, 2010, 36(6): 594-604.

DOI：10.1252/kakoronbunshu.36.594

• Hematite Particles
• Self-assembly Structures
• Optical Microscopic Observations
• Radial Distribution Functions
• Monte Carlo Simulations

Structural analysis of a self-assembled layer with lattice-like structures composed of cubic hematite particles with the side length of approximately 0.9 mu m were carried out by means of radial distribution functions (RDFs). The cubic particles were synthesized by aging a solution of FeCl(3) for 8 days at 373 K. The RDFs were determined by a digital image analysis method from the direct optical microscope observation of the particles. Two-dimensional Monte Carlo simulations of the cubic hematite particles were also carried out in order to clarify the influences of a weak magnetic field and magnetic interactions between particles on the lattice structure. In the case of very weak geomagnetic fields, chain-like and square lattice structures were formed on a glass plate through the sedimentation process of the particles. The simulation results revealed that the square lattice structures are stabilized by the zigzag orientation of the magnetic moments of the particles. In the case of relatively strong magnetic fields, a broad shoulder appeared at a slightly longer distance from the first peak position in the experimental RDF. This corresponds to the three small peaks that appeared in the simulated RDF for an ideal monodisperse system. This suggests that energetically stable oblique lattice structures are formed with magnetic moments aligned to the field direction.

• 出版日期2010