Signal Enhancement of 0.2/spl mu/m Packed Domain Using Magnetic Domain Expansion Readout Disk with a Gating Layer

Magnetic domain expansion readout under the condition of no alternative magnetic field are studied. The reproduced waveform of a 0.2 /spl mu/m domain has a very sharp shape and large amplitude of 70% to the saturated signal level. It is found that the linearity of the readout signal including domain expansion phenomenon is maintained as well as a conventional readout, therefore relatively clear reproduced signal of the 0.2 /spl mu/m packed domain can be detected. In order to improve it, the sharper readout waveform must be reproduced by using a gating layer between the expansion and the recording layers, and the readout signal of the 0.2 /spl mu/m packed domain is enlarged two times relative to that without a gating layer.