Effect of medium permeability on the perpendicular recording process

Abstract

Articles you may be interested inThe effects of oxygen on intergranular exchange and anisotropy dispersion in Co ∕ Pd multilayers for perpendicular magnetic recording media J. Appl. Phys. 99, 08E708 (2006); 10.1063/1.2162487Reverse dc erase medium noise analysis on exchange-coupling effect in coupled granular/continuous perpendicular recording media

The transition from longitudinal to perpendicular recording

“…This imaging has also been referred to as an interaction between head and medium [69,70]. An alternative way to describe this phenomenon is to assign to the medium a permeability greater than one [71]. On the other hand, it has to be said that both the pole and the SUL may be saturated during the writing process and consequently the imaging effect is destroyed.…”

Unshielded Perpendicular Recording Head for 1 Tb/in>tex<$^2$>/tex<

“…Effective media permeability is calculated using (1) Current 1 Tb design uses media of magnetization of approximately 700 emu/cm and anisotropy field of around 18 kOe. Owing to the nonzero magnetic susceptibility of the media, reluctance arguments suggest that the head would see a thinner media than it is physically [3]. Therefore, 20-nm-thick media would appear as 13 nm thick for permeability of 1.5.…”

“…In all cases, the upper areas of the head (nontip region) were approximated by vertically oriented magnetizations (saturated for write field calculations, zero for remanent calculations); in other words, the nontip regions are not treated micromagnetically. The head-media interactions have been treated in an empirical way [3] using a media permeability of 1.5. Effective media permeability is calculated using (1) Current 1 Tb design uses media of magnetization of approximately 700 emu/cm and anisotropy field of around 18 kOe.…”

Investigations of Perpendicular Write Head Design for 1>tex<$hboxTb/in^2$>/tex<

“…There is a strong dependence of medium thickness on the effective write field, i.e., the thicker media will degrade the writability. An argument for using a thicker medium layer based on the permeability of the recording layer effectively reducing the medium thickness is made by Victora [4], [18]. However, more recent investigations [19] have indicated only an approximate 10% gain in the write field for the case when the pole tip of the head is not fully saturated.…”