QUASI-2-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 H(C1)(phi) and H(C2)(phi), where phi 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 much greater than H(C2).