Pattern analysis of magnetic stripe domains morphology and topological defects in the disordered state

Abstract

Abstract A direct-space analysis of globally disordered (‘labyrinthine’) stripe domain patterns in thin ferrimagnetic garnet films is presented. A set of algorithms, designed to encode and analyse line patterns, serves to identify and correlate the positions of topological defects, and to delineate structural motifs in the pattern morphology. Despite the fact that labyrinthine patterns represent a metastable state, statistical analysis of morphological and certain geometrical features extracted via pattern analysis reveals that the labyrinthine state's structure is well defined and robust; it is composed of oblong polygonal regions of ‘smectic’ ordering of its constituent line segments. That is, there exists a well defined length scale in these globally disordered labyrinths over which the ordered lamellar state of minimal free energy is realized; this length scale corresponds to a characteristic size of the ordered regions (‘segment clusters’). Furthermore, local orientational correlations of adjacent se...