Challenges in the practical implementation of perpendicular magnetic recording

Investigation of High Density Magnetic Recording with Single-layer Perpendicular Media

“…The reversed domain formation is also a thermally stimulated process which reduces the recorded signal intensity of perpendicular recording media. This type of signal decay can be suppressed by employ~ng thicker perpendicular recording media and/or by employmg media with high Mr/Ms ratio [47,48]. The decay rate can also be decreased by using recording media with high perpendicular anisotropies [38].…”

“…In this case, however, the squareness of the M -H curve seems to be little degraded by reducing the exchange coupling. An optimization is required to keep the high MrIMs ratio which is useful to keep a high reproduced output as well as to avoid the signal decay coming from demagnetization effect at low linear densities [40,47]. The M -H curve of Co-alloy single-layer perpendicular media can be improved by introducing the dual-under layer[4J2].…”

Thermal Relaxation in Perpendicular Recording with Single Pole Head and MR Head

“…It has been reported that little time decay of output was measured using a MIG type ring head for recording/narrow gap ring head for readback in perpendicular recording [1]. On the other hand, a severe reduction of signal has also been reported [2]. In our experiments, a single-pole writing head and a highly sensitive MR reproducing head was used to measure the output time decay in double-layered media.…”

Soft-decision decoding of MTR codes over magnetic recording channels

“…Pored toga što postoje određeni tehnički izazovi [55]- [57], predviđanja su da će u čitavoj industriji magnetskog memorisanja u narednih par godina tehnologija prependikularnog zapisa u potpunosti biti spremna za sisteme sa terabitnim površinskim gustinama [11].…”

“…Kada je prisutan par ulaznih grešaka (e x1 , e x2 ) takav da njihove filtrirane grešake, u pojedinim stazama, zadovoljavaju (55) gde ε o = 0,268 predstavlja presečnu tačku (52) …”