Domain Dynamic Phenomena of Domain Expansion Readout Disk (MAMMOS)

MAMMOS (Magneto Optical Amplifying Magneto Optical System) is one solution to amplify extremely small magneto-optical signal reproduced from a very tiny domain which is recorded as a high areal density. Especially, in the case of MAMMOS with alternative external readout field, the enhanced signal reaches to the saturated signal level, even if the small domain size is 0.1 μm in length which is one tenth compared to the laser spot size. The domain expansion phenomena suddenly happen beyond a critical readout power or external field, that is, it is independent of the domain size. The critical phenomena depend on the critical magneto-static coupling between the expansion layer and the recording layer.