Metal Particulate Medium for Ultra High Density Recording

Metal particulate (MP) test tape was prepared with playback characteristics nearly as good as those of ME tape, using very fine metal particles (average length 0.175&3x003BC;m) with average axial ratio 9, employing techniques for high dispersion and longitudinal orientation. In essence, these techniques are conventional; however, the test tape boasts superior characteristics making it suitable for use in ultra-high density recording, including a surface roughness of 3.63 nm (R
_rms
) and a squareness ratio of 0.89. Playback characteristics are also superior: the output level is only 1.5 dB lower than for ME tape at 100 kFRPI. In this paper, we describe the recording density characteristics of this test tape, and demonstrate the effect of an improved squareness ratio and surface roughness on the high-density characteristics, as well as the effect of employing heads with different B
_s
on the latter characteristics.