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We have successfully demonstrated longitudinal recording at areal density of 130 Gb/in2 at a data rate as high as 170 Mbps (21 MB/s) and at a bit-aspect-ratio (BAR) of 2.9, using merged inductive-write/spin-valve-read heads on low noise thin film disks. The heads were fabricated with the standard photolithography and wafer pole trimming used in our currently available commercial products. The reader is a bottom synthetic spin valve (BSSV) with a 0.09 μm gap, and the writer has a conventionally trimmed pole with 0.09 μm gap. The reader magnetic read width (MRW) was measured at 0.10 μm. At read bias of ∼4 mA we measured reader sensitivity as high as 20 mV/μm. The write head was also optimized for tracks as narrow as 0.14 μm operating at overwrite (OW) of 36 dB and nonlinear transition shift (NLTS) better than −25 dB at 610 kBPI, without precomp. Using conventional media we measured total spectral SNR∼18 dB. The media to electronics noise ratio was 4.8, showing that we are still operating in a media noise limited system. Low-flying air bearing surface (ABS) design and advanced pole tip recession (PTR) control were required to achieve magnetic spacing of about 15 nm.

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Sputter deposited FeRhN films with a value of more than 20 kG were used as high moment flux enhancement layer in the write element in order to achieve a recording density of 63.2 Gb/in 2 . This layer was disposed between write gap and upper portion of the top pole, which was made of Ni 45 Fe 55 with a of 16 kG. A 36 dB overwrite and nonlinear transition shift of less then 20 dB were obtained at this recording density. A finite element model was used to calculate the longitudinal field and field gradient at the medium location. The results suggested significant increases of both by incorporating the flux enhancement layer.

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