Developments and advances in thin layer particulate recording media

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 Ba-ferrite 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 +9 dB 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.