Reversal in Bit Patterned Media With Vertical and Lateral Exchange

Abstract

The extent to which dipolar interactions affect switching field distributions and thermal stability, and subsequently system performance, depends closely on the areal density, materials properties, and the architecture of the media, as well as the recording scheme and field profiles. This paper assesses, via micromagnetic simulations, the potential of heterogeneous capped bit patterned media and other proposed patterned media designs for ultra-high-density magnetic recording with respect to writability, switching field distributions, and thermal stability at different areal densities. Such media is comprised of an array of homogeneous or exchange coupled composite elements with vertical anisotropy that is ferromagnetically or antiferromagnetically coupled to a continuous horizontal layer. It is shown that such systems, characterized by lateral and vertical exchange, enable ultra-high-density recording at low switching fields while ensuring high thermal stability and low switching field distributions. Mechanisms leading to improved performance in capped systems are investigated. Structural and material considerations are provided for all media models.Index Terms-Magnetic recording, magnetization reversal, magnetic thermal factors.

Template-Assisted Direct Growth of 1 Td/in2 Bit Patterned Media

“…The iSFD can be further improved by using an exchange coupled composite structure in the magnetic recording layer. 14 We confirmed the high quality of the TG BPM media by performing bit error rate measurements using a drag tester with commercially available HDD heads. The details of our experimental setup can be found in ref 15.…”

“…Furthermore, the intrinsic switching field distribution (iSFD/Hc) is improved from 50% to 11% by using new epitaxial method. The iSFD can be further improved by using an exchange coupled composite structure in the magnetic recording layer 14 . We confirmed the high quality of the TG BPM media by performing bit error rate measurements using a drag tester with commercially available HDD heads.…”

Bit-Patterned Magnetic Recording: Theory, Media Fabrication, and Recording Performance

“…Adoption of block copolymer selfassembly (see Section IV-B) resulted in tighter fabrication tolerances and an immediate improvement in SFD/HC (see Fig. 6) [17]. At an AD of 500 Gd/in 2 (hexagonal pitch = 39 nm) SFD/HC dropped from 12-18% down to 8-9%.…”

“…The first is the intrinsic switching field distribution iSFD, and the second is the data dependent dipolar interaction field distribution dipole. The interaction fields in BPM are typically only dipolar, though it is possible to create exchange bridging among the islands [16], [17]. If the various sources are uncorrelated Gaussian distributed variables, we find   (…”

Overcoming the Trilemma Issues of Ultrahigh Density Perpendicular Magnetic Recording Media by L10-Fe(Co)Pt Materials

“…155 Overcoming the Trilemma Issues of Ultrahigh Density PMR engineering of the media alone. Besides ECC, energy assisted recording such as HAMR and MAMR [156][157][158] is one of the promising schemes to combine with BPM in order to overcome the writing¯eld limit of L1 0 -Fe(Co)Pt-based media. These combined approaches may very well be what are ultimately needed to push the areal density towards 10 Tbit/in 2 .…”