Modeling and experimental results are presented for keepered longitudinal recording media and planar (undershoot-reduced) thin film recording heads with low flying heights for areal densities >1 Gb/in.2. The keeper layer is magnetically coupled to the medium magnetic transitions, reducing the transition demagnetization and narrowing the transition length by about 10% in the media after recording. The reproduced bias field and the transition fields combine in the keeper to produce a partially saturated region, thereby modifying the fields from the medium transitions at the head during playback. We present experimental data on the write and read process for keepered media. Boundary element model results are presented which explain the amplitude gain and pulse asymmetries observed experimentally. Use of a keepered medium allows areal density improvements >20% through higher bits per inch.
The presence of as little as 2.3×10−5 Pa (1.73×10−7 Torr) of residual nitrogen gas in an rf sputtering chamber has been found to promote the formation of the fcc phase in Co-Cr films under conditions otherwise favorable to the formation of the hcp phase. The fcc phase follows the disorientation of the hcp phase as the nitrogen partial pressure or throughput increases. The occurrence of the fcc phase is directly related to the partial pressure or throughput of nitrogen in the system as shown using controlled leaks of both pure nitrogen and air. The nitrogen may destroy the columnar microstructure and the film perpendicular magnetic anisotropy which is due to the well-oriented hcp phase. This sensitivity to nitrogen in the background gases makes it necessary to achieve a low background pressure in the sputtering chamber if films with perpendicular magnetic anisotropy are to be obtained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.