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 Y<sub>3</sub>Ga<sub>x</sub>Fe<sub>5−x</sub>O<sub>12</sub> 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.