Takahiro Korenari

FeN phase generation effects for high moment FeTaN films

FeN phase generation has been observed by x‐ray analysis in FeTaN films, which normally show α‐Fe, TaN phase, and no FeN phases. With a rise in substrate temperature Ts above 200 °C, FeN phases are generated in nitrogen reactive sputtering process with columnar structure formation, and remain after annealing. With FeN phase generation, coercivity Hc and magnetostriction λ values increase markedly. Moreover, internal stress σ for the films increases drastically. The FeTaN films, sputtered on low temperature substrate, generate no FeN phases, and show low Hc, about 0.1 Oe, and low λ. Consequently, FeN phase generation with columnar structure formation has negative effects for FeTaN films to be used as magnetic head core materials. For preparation of FeTaN films, the substrate temperature has to be controlled to a sufficiently low value for suppression of FeN phase generation.

Analysis of track-edge noise in thin-film recording media

Track-edge noise has been analyzed to clarify track-edge noise mechanisms. Edge noise arises from two different regions: the bit edge where the magnetization direction is opposite to the previously dc-erased direction and the magnetic transition edge. The edge noise at low density is mainly due to the magnetic distribution at the bit edge. The transition edge noise increases with increasing recording density, and it becomes dominant at high-recording density for an oriented medium. On the other hand, the transition edge noise is almost constant with increasing recording density for an isotropic medium.

Offtrack characteristics on media noise for Co-Cr-Ta films

The effect of remanent magnetic flux density (B/sub r/) and magnetic layer thickness (/spl delta/) on offtrack noise characteristics in Co-Cr-Ta alloy thin films is investigated. It has been found that decreasing the value of B/sub r/ is a more effective method of improving offtrack noise characteristics than decreasing the value of /spl delta/. Offtrack noise is shown to be due to the fluctuations in the amplitude of readback waveforms, fluctuations which are caused by fluctuations in magnetic transition amplitude. It was observed, using a magnetic force microscope, that lower B/sub r/ media had sharp boundaries at the track edge regions and the magnetization was more uniform, compared with those of higher B/sub r/ media.