Demonstration and characterization of 130 Gb/in2 magnetic recording systems

Abstract

We have successfully demonstrated longitudinal recording at areal density of 130 Gb/in2 at a data rate as high as 170 Mbps (21 MB/s) and at a bit-aspect-ratio (BAR) of 2.9, using merged inductive-write/spin-valve-read heads on low noise thin film disks. The heads were fabricated with the standard photolithography and wafer pole trimming used in our currently available commercial products. The reader is a bottom synthetic spin valve (BSSV) with a 0.09 μm gap, and the writer has a conventionally trimmed pole with 0.09 μm gap. The reader magnetic read width (MRW) was measured at 0.10 μm. At read bias of ∼4 mA we measured reader sensitivity as high as 20 mV/μm. The write head was also optimized for tracks as narrow as 0.14 μm operating at overwrite (OW) of 36 dB and nonlinear transition shift (NLTS) better than −25 dB at 610 kBPI, without precomp. Using conventional media we measured total spectral SNR∼18 dB. The media to electronics noise ratio was 4.8, showing that we are still operating in a media noise limited system. Low-flying air bearing surface (ABS) design and advanced pole tip recession (PTR) control were required to achieve magnetic spacing of about 15 nm.

Patterned media for future magnetic data storage

“…2 and technology demonstrations of 130 Gb/in. 2 have been published (Stoev et al 2003). Very recently, companies have announced technology demonstrations of greater than 230 Gb/in.…”

Giant Exchange‐Bias in Polyol‐Made CoFe2O4‐CoO Core–Shell Like Nanoparticles

“…It is usually characterized by an asymmetric hysteresis loop and an enhanced coercive field, H C . This feature is the origin of several active applied researches, since it can be used for magnetic recording heads, magnetoresistive random access memories (MRRAM), permanent magnets, and high‐density granular magnetic recording media . A number of excellent reviews on the subject have been published reporting EB in differently shaped nanomaterials: bilayer systems, core–shell nanoparticles (NPs), nanomagnets embedded in an AF matrix, and spin‐glass phases in nanostructures .…”

Exchange bias effect in alloys and compounds

“…However, in most of the cases theories were limited to specific problems where intricate structures at the interfaces were simplified. Until now, EB effects have been exploited in several technological applications such as read head of recording devices [39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54], magnetoresistive random access memories (MRRAM) [55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76] and it has been proposed for the technological applications in stabilizing magnetization of superparamagnetic nanoparticles [77,78,79,80] or to improve coercivity and energy product of the permanent magnets [81,82,83,84].…”