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Nanoscale perpendicular magnetic island arrays fabricated by extreme ultraviolet interference lithography Appl. Phys. Lett. 92, 102505 (2008); 10.1063/1.2841821Dot-by-dot analysis of magnetization reversal in perpendicular patterned CoCrPt medium by using magnetic force microscopy

We describe a magnetic recording media composed of antiferromagnetically coupled (AFC) magnetic recording layers as an approach to extend areal densities of longitudinal media beyond the predicted superparamagnetic limit. The recording medium is made up of two ferromagnetic layers separated by a nonmagnetic layer whose thickness is tuned to couple the layers antiferromagnetically. For such a structure, the effective areal moment density (Mrt) of the composite structure is the difference between the ferromagnetic layers allowing the effective magnetic thickness to scale independently of the physical thickness of the media. Experimental realizations of AFC media demonstrate that thermally stable, low-Mrt media suitable for high-density recording can be achieved.

Isolated tracks of magnetic single-domain islands have been fabricated by patterning perpendicular Co70Cr18Pt12 continuous films using focused-ion-beam lithography, reaching areal densities as high as ∼200 Gbit/in2. We demonstrate writing and reading of individual islands using a quasistatic write/read tester. We present results on transition position jitter and signal-to-noise ratio (SNR) for patterned media and compare them with those on equivalent unpatterned strips of the media. We observe that patterning dramatically reduces jitter and improves SNR, which is independent of track width. Moreover, the synchronization requirements needed for writing bits in patterned media was investigated on a single row of islands revealing a significant “write window,” where islands can be written correctly, of about half the island period.

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