The recording performance of a new magnetic tape based on ultra-fine, perpendicularly-oriented BaFe particles was investigated. Specifically, using a low lateral tape motion demonstration platform, a new servo pattern written on the advanced perpendicularly oriented BaFe medium, a new low friction head technology, a novel synchronous servo channel design, and advanced servo control concepts, we were able to demonstrate a record closed-loop track-follow performance with a 23.4 nm standard deviation of position-error signal, roughly one order of magnitude better than in current tape products. In addition, using read back waveforms captured on the same advanced perpendicularly oriented BaFe medium with a 0.2-m-wide data reader, we demonstrated write/read performance at 518 kbpi using advanced noise-predictive maximum likelihood (NPML) detection schemes. Combining these two results, we estimate that the new medium can support an areal recording density of up to 29.5 Gb/in 2 . This result demonstrates the scalability and extendability of tape technology using low-cost particulate media.

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We study noise and recording properties of nonoriented barium-ferrite particulate media using micromagnetic modeling. The packing and orientation distribution of the barium ferrite particles are reproduced very well with our packing algorithm. The distribution of switching fields is determined from experimental hysteresis loops. Using these parameters, we perform recording simulations of periodic waveforms written at various frequencies and extract broad-band signal-to-noise ratio (BB-SNR). Comparison to experimental measurements shows very similar signal and noise characteristics, with however a 6 dB offset in BB-SNR values. Other (e.g., mechanical) noise sources would need to be included in the simulations to account for the difference. Nevertheless, the simulations prove very useful to understand and quantify how particle and media parameters contribute to the signal-to-noise ratio. For the present nonoriented particulate medium, we verify that the particle volume distribution affects the noise power according to the existing analytical expression for particulate noise. The particle anisotropy distribution is found to significantly affect the signal roll-off. The related variation in BB-SNR is found to be in good quantitative agreement with experiments. The effects of other parameters on BB-SNR, such as dipolar coupling, medium thickness, and average head-medium spacing, are also presented. An analytical slope model is proposed for nonoriented media that reproduces the simulations and experimental data very well.