85.9 Gb/in<inline-formula> <tex-math notation="LaTeX">$^{ {2}}$ </tex-math></inline-formula> Recording Areal Density on Barium Ferrite Tape

Abstract

The recording performance of a new magnetic tape based on perpendicularly oriented barium ferrite particles was investigated using a 90-nm-wide giant-magnetoresistive reader and a prototype enhanced-field write head. A linear density of 600 kb/in with a postdetection byte-error rate <;3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> was demonstrated based on measured recording data and a software read channel that used a noise-predictive maximum likelihood detection scheme. Using a new iterative decoding architecture, a user bit-error rate of <;1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-20</sup> can be achieved at this operating point. To facilitate aggressive scaling of the track density, we made several advances in the area of the track-following servo. First, we developed an experimental low-noise tape transport. Second, we implemented an optimized servo channel that together with an experimental timing-based servo pattern enables the generation of position estimates with nanoscale resolution at a high update rate. Third, we developed a field-programmable gate array-based prototyping platform in which we have implemented the servo channel and an H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -based track-following controller, enabling real-time closed-loop track-following experiments. Combining these technologies, we achieved a position-error signal (PES) with a standard deviation of 10.3 nm. This magnitude of PES in combination with a 90-nm-wide reader allows the writing and reading of 177-nm-wide tracks at 600 kb/in, for an equivalent areal density of 85.9 Gb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . This paper clearly demonstrates the continued scaling potential of tape technologies based on low-cost particulate media.