High Speed Magnetic Field Modulation in Pit-Edge Magneto-Optic Recording

As one approach to high-speed high-density magneto-optical disk systems, we studied the possibility of using pit-edge recording with magnetic field modulation, enabling data overwriting. Because in field modulation recording the accuracy of edge positioning is determined in the zero-field region where domain formation is unstable, it is essential that a short field switching time be achieved. As part of this work, we developed a magnetic head and driving circuitry for use in field modulation magneto-optical recording, and attained a field switching speed of about 25 Oe/ns. As a result, it should be possible to develop a system with a data overwrite function, with a data transfer rate of 15 Mbps, comparable to that of 5" rigid disk drives.