Elements of cellular domain patterns in magnetic garnet films

Cellular patterns of magnetic domains observed in uniaxial garnet films are comprised of three elemental domain structures: stripe segments, threefold vertices that join these segments, and pentagonal structures that join five segments and contain trapped magnetic bubbles. We report observations of the stability and dynamics of these structures and show how they govern the evolution of cellular patterns in an external bias field $H_B$. Energy localized in the stripe segments acts as tension that drives the domain motion. A simple extension of the conventional model of stripe domains incorporates domain interactions in sparse patterns and gives access to the bias and configuration dependence of the stripe tension. We apply this formulation to an array of stripe domains to characterize the tension that arises in nonequilibrium patterns. Comparison with experiment indicates that sparse, disordered (mazelike) stripe patterns maintain equilibrium as $H_B$ is monotonically increased and shows the expected divergence in stripe spacing at $H_B$=$H_{\mathrm{RI}}$, where $H_{\mathrm{RI}}$ is the run-in field for isolated stripe domains. In contrast, cellular patterns persist to $H_B$>$H_{\mathrm{RI}}$, where the patterns are far from equilibrium.