Effects of Ar pressure during CoCrPt sputter-deposition on read/write and related properties of CoCrPt/Cr magnetic recording media formed at low temperatures

Abstract

Structures, magnetic properties and read/write properties were studied for low-temperature-growth CoCrPt/Cr magnetic recording media, of which CoCrPt films were sputter-deposited under various Ar pressures. Increase of Ar pressure causes both isolation enhancement and size decrease of CoCrPt grains, which are epitaxially grown on Cr grains. Coercivity increases as Ar pressure increases upto 20–30 mTorr. With an increase of Ar pressure, fluctuation field increases more rapidly than the case when the magnetic film thickness is decreased. Consequently, an increase of Ar pressure for sputter deposition significantly decreases medium noise with a slight decrease of output signal. The highest signal-to-noise ratio of 26.4 dB for 75 kFCI recording was obtained with the Ar pressure of 30 mTorr. This fabrication technique, which requires neither a thick Cr underlayer nor a Cr underlayer deposited under high Ar pressure, is especially suitable for the media with plastic substrates.