Formation and evolution of giant dynamic domains in an ac magnetic field

Magnetization reversal in ferrite-garnet films placed in an ac magnetic field, bringing about the formation of metastable dynamic domains with sizes exceeding those of quasi-static domains by an order of magnitude or greater, was studied using a stroboscopic method. The formation of giant dynamic domains (GDDs) is due to the finite domain wall velocity and depends on the density of domain nucleation centers. It was shown that the GDD comblike boundary forms during the part of a field period near the moment of field polarity change. GDDs arise when the dynamic hysteresis loop shape changes from a triangle to an ellipse.