Experimental investigation of domain expansion speeds in MAMMOS

The speeds of the domain expansion and collapse processes in a magnetic amplifying magneto-optical system (MAMMOS) recording system were experimentally measured with a high-speed photodetector. Data was collected for a range of read powers and field values, the average rise and fall times were extracted, and the delay between the field switching and the domain collapse was examined. The minimum measured expansion and collapse times were 1.6 and 4.5 ns, respectively, and the field switching to collapse delay was found to be about 20 ns with a spread of 20 ns. Theories on the expansion and collapse processes and an explanation of the delay are presented.