Thin layer particulate recording media with a nonmagnetic under layer have been developed with double coating techniques, and their high density characteristics have been confirmed to be excellent. Such media produce a higher output than single and thick layer media because they have a smooth surface resulting from the under layer smoothness and less demagnetization resulting from the thinness of the magnetic layer. Such media produce a sharp and symmetrical isolated pulse waveform and show good overwrite characteristics for digital recording. The application of Baferrite particles to thin layer media, in addition to metal particles, has clarified the differences between the characteristics of the two media. The output of thin layer metal media has been improved by up to +9dB compared with the value for reference metal media, largely by improving the metal particles. Thin layer Ba-ferrite media are characterized by high output and low noise in the short wavelength region. Such performance will be expected for any particle orientation.

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We tried to realize Gbits/in 2 class Floppy Disk with a magnetic layer prepared by sputtering (SP-FD). The heat-durable undercoat and the underlayers made magnetic layer have Gbits/in 2 properties, with higher S/N and narrower PW50 in comparison with those of 3.1 Gbits/in 2 HD. Heat durable substrate, fine protrusions and aerodynamics consideration allowed to achieve stable and nonaggressive contacts and good durability after running for more than 250 hours at three different environment conditions. We can conclude that the SP-FD has the potential of 3Gbits/in 2 FD Index Terms-Magnetic recording, head-disk interface, thin film, floppy disk.

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