Quasi-two-dimensional domain structures of magnetic particles in a static field

An array of magnetic-particle chains is assembled and aligned in a magnetic field H, and its structures are studied by small-angle light scattering. The system undergoes a series of structural changes: single particles → disordered anisotropical domains → array of strongly correlated columns, as H increases. Different structure regions are separated by two critical field lines ${\mathit{H}}_{\mathit{C}1}$(φ) and ${\mathit{H}}_{\mathit{C}2}$(φ), where φ is the concentration of the particles. Due to disorders inherited in the self-assembling process, the magnetic columns remain short-range ordered even in the strong-field limit, H≫${\mathit{H}}_{\mathit{C}2}$.