The effects of Sendust keeper thickness, Cr break-layer thickness and reproduce bias on keepered media performance and pulse asymmetry

Keepered media optimal Sendust keeper thickness is 15 nm (2.06 memu/cm² MrT) in terms of amplitude, pulse width and peak detect channel performance. Keeper noise is partially coherent and is larger at low densities with minimum values for <15 nm keeper thickness. Performance improves as Cr break layer is reduced to 2.0 nm thickness. Keepered media amplitude and peak position asymmetry are a function of bias and must be corrected to do measurements of overwrite, partial erasure and NLTS and to achieve maximum linear storage density