Longitudinal recording on a rigid disk using Ba-ferrite powder

We propose a new concept for a Ba-ferrite coated disk, in which the Ba-ferrite particles are longitudinally oriented and to which acicular Co-γFe2O3powder is also added, to achieve high density recording and low noise characteristics for rigid disk applications. By using a ring head, longitudinal orientation was found to be effective in obtaining an increased output and a symmetrical waveform. Acicular powder is added to reduce pinholes upon longitudinal orientation. Although the critical bit density, D50, decreases slightly, practical recording density, judged from the degree of peak shift, is larger for longitudinal orientation than for perpendicular orientation. The new disk has great promise for applications of more than 40 kFRPI, without any change to conventional disk drives and ring-shaped heads.