To overcome the high sensitivity of the signal-to-noise ratio (SNR) to the switching field distribution in the perpendicular media, we proposed to use tilted media in the perpendicular recording system in this letter. It was found that a much better tolerance of the easy-axis distribution could be achieved when tilted media were used instead of perpendicular media in a perpendicular recording system. We then analyzed the range of the switching field at the freezing points, and found that high Ku magnetic material is feasible in tilted media. The results indicated that the areal density could be more than 62% higher than that of perpendicular media when 45° easy-axis tilted media with Ku=7.0×106 erg/cm3 were used. Finally, simulation of the switching dynamics revealed that a much faster magnetization switching could be achieved in 45°-tilted media than in perpendicular media.

A layered structure to improve the antiferromagnetic exchange coupling constant (J) in laminated antiferromagnetically coupled (LAC) media is proposed. This structure has a much larger thermal stability in comparison to simple LAC structures. It also improves the coercivity and decreases the remnant moment-thickness product to achieve a high resolution and a low pulse width. The recording measurements indicate that this structure has a slightly larger noise than the simple LAC structures. However, its overall signal-to-noise ratio (SNR) is comparable to that of the simple LAC structures. High SNR and much higher thermal stability make this structure suitable for ultrahigh areal densities.

We demonstrate that periodic magnetic nanostructures can be fabricated by depositing perpendicular magnetic films on self-assembled surfaces by ion beam bombardment. Similar stripe domain patterns and reduced coercivity are observed for the as-deposited sample as compared with those for a reference sample with unbombarded substrate. Further processing steps such as etching and polishing will be needed to isolate the magnetic elements from each other, in order to make ultrahigh density magnetic storage media.

Structure of nitrogenated carbon films prepared from acetylene and nitrogen mixture in electron cyclotron resonance plasmaNitrogenated tetrahedral amorphous carbon ͑N:ta-C͒ films prepared by the filtered cathodic vacuum arc technique were studied by x-ray photoelectron spectroscopy ͑XPS͒, Raman spectroscopy, spectroscopic ellipsometry, ultraviolet photoelectron spectroscopy and temperature dependent resistance measurement. As the nitrogen flow rate varies from 0 to 20 sccm, the nitrogen content in the deposited film increases from 0 to 4.6 at. %. Curve fitting of the C 1s and N 1s XPS spectra shows that the C-C sp 3 fraction decreases with an increase in nitrogen content and that the nitrogen atoms are mainly bonded in sp 2 C-N bonds. The pure ta-C film has a work function of 4.35 eV and the N:ta-C films have a value around 4.55 eV. With an increase in nitrogen flow rate, the intensity ratio of the D peak to the G peak, I D /I G increases monotonously from 0.44 to 1.25 and the G peak width decreases from 220 to 199 cm Ϫ1 . The Tauc optical band gap decreases from 2.2 to 1.8 eV.

The face-centered-tetragonal-(001) FePt thin films were prepared by dc magnetron sputtering Fe50Pt50 layer onto Cr91Ru9 underlayer at 400 °C. In order to enhance the coercivity and to obtain a relative lower exchange coupling medium with nucleation reversal mechanism, a nonmagnetic Ru pinning layer inserted in the magnetic layer is described to introduce controllable defects to impede domain-wall motion. A 60% increasing of the out-of-plane coercivity was observed after 1 nm Ru nonmagnetic pinning layer added between the FePt magnetic layers. From angular dependence of the coercivity measurement, the magnetization reversal mechanism was observed to shift from the typical domain-wall motion behavior to the nucleation mode by increasing the thickness of the pinning layer.