The role of NiAl underlayers in longitudinal thin-film recording media

Abstract

Longitudinal recording media made with chromium and with nickel-aluminum underlayers are compared. NiAl films have smaller grains and random crystallographic orientation, while Cr films have larger grains and either a ͕110͖ or a ͕200͖ preferred orientation depending on the deposition conditions. Cobalt alloy films grown on NiAl have nearly random crystallographic orientation and significant c-axis out-of-plane component, and lower hysteresis loop squareness and coercivity than films made on a heated Cr underlayer. NiAl-underlayer media do not exhibit in-plane magnetic anisotropy induced by the substrate texture lines. CoCrTaPt/Cr/NiAl media had higher overwrite than CoCrTaPt/Cr media due to higher coercive squareness and a sharper hysteresis loop closure.

NiAl Seed Layer for Obliquely Sputtered Thin-Film Tape

“…The intensity of this diffraction peak is relatively weak in comparison with the (110) diffraction peak of Cr with the same thickness. It is consistent with literature, where the (110) texture is often observed for NiAl sputtered on glass, Si, or polymer substrate at room temperature [3]- [5]. However, the diffraction peak of the (112) plane is not visible indicating a very weak texture or random distribution of this plane.…”

“…However, the diffraction peak of the (112) plane is not visible indicating a very weak texture or random distribution of this plane. This result is in agreement with the result of NiAl films grown by dc sputtering [5]. However, this differs from the reported NiAl films deposited by radio-frequency sputtering where the (112) texture is observed 0018-9464/04$20.00 © 2004 IEEE [3], [4].…”

Medium noise and grain size analysis of CoCrPt/Ti perpendicular media with NiAl seed layer

“…The average grain diameters of the bi-layer and the tri-layer media are 10.7 nm and 8.2 nm, respectively. These values are smaller than the value of 12 nm for longitudinal medium with a NiAl layer [5], [6]. The CoCrPt film thickness is 20 nm for both types of perpendicular media.…”

“…NiAl/Cr underlayer structures enhance orientation for Co hcp alloy, which is not suitable for perpendicular media. However, the NiAl film does not strongly influence the orientation of longitudinal media itself [6]. Therefore, medium orientation can be controlled by using layers were deposited by using a Balzers Process Systems Circulus M12 sputtering system.…”

Grain size effect of Ni–W–Cu seed layer film upon signal-to-noise ratio for PMR application

“…The common material of seed layer is Ni-based alloy. However, the NieAl intermediate layer traditionally used in LMR [4e6] does not appear a strong crystallinity in FCC(111) [7]. For PMR, NieW alloys with FCC(111) preferred orientation and good thermal stability have became a splendid candidate as a seed layer [8e10].…”