DYNAMIC BEHAVIOR OF DOMAIN WALLS IN LOW-MOMENT YTTRIUM-GALLIUM-IRON GARNET CRYSTALS

Abstract

Measurements of domain-wall velocity, using the ``bubble collapse'' technique, in Y3GaxFe5−xO12 crystals with 1.0 ≤x≤1.7 show that the usual ``viscous'' damping model of domain-wall motion does not apply. At fields less than about 1 Oe above the threshold H0, the wall mobilities are greater than 103 cm/sec Oe. A few oersteds above the threshold, the field dependence of the wall velocities changes abruptly and, at higher fields, the velocities depend linearly on (H-H0)1/2.