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This article reports on the properties of the media prepared on glass substrates which were used in IBM’s 10 Gbit/in.2 demonstration. In order to support a linear density of 315 kbpi and a track density of 33 ktpi, the remanant coercivity Hcr and remanant moment thickness product Mrt of the magnetic layer were 3450 Oe and 0.37 memu/cm2, respectively. The media used a NiAl seed layer, a CrV underlayer, a Co alloy magnetic layer, and a carbon overcoat protection layer. The magnetic film had a grain size of 12 nm as observed by transmission electron microscopy. The preferred orientation (PO) of the magnetic layer was (101̄0). This PO enables one to sustain high coercivities at low values of Mrt. It is observed that the c-axis in-plane texture of the magnetic layer is critical to achieve a low noise medium. Using a focused-ion-beam (FIB) trimmed giant magnetoresistance head and conventional partial response maximum likelihood channel, the on-track-error rates were measured at the 10−10 level.

The classic problem of heat flow in multilayer film structures has been revisited from the perspective of engineering applications for fields such as optical storage media design, laser annealing of semiconductor materials, electron beam lithography, and ion implantation. A compact recursive structure N-layer Green’s function is developed from the coupled partial differential equations of thermal conduction. Temperature profiles are calculated for the absorption of normally incident continuous and pulsed-Gaussian-beam irradiation, on both static and moving media, with variable absorption across the source layer. General beam, amplitude-time dependencies can be calculated with this formalism; however, only simple rectangular pulses are treated in the text. General N-layer solutions are developed, and compact, recursive-integral formulas, whose evaluation is enhanced with modern computer languages such as c and apl, are derived. In addition, we offer a clear physical interpretation of the results expressed by the mathematics, which is a key element that aids successful application of the results to engineering design problems. The physics illuminated by the mathematics suggests a path toward optimal design of the media for enhanced performance, irrespective of the specific application.

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