The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²

Abstract

This paper reviews the state of the head-disk interface (HDI) technology, and more particularly the head-medium spacing (HMS), for today's and future hard-disk drives. Current storage areal density on a disk surface is fast approaching the one terabit per square inch mark, although the compound annual growth rate has reduced considerably from ∼100%/annum in the late 1990s to 20-30% today. This rate is now lower than the historical, Moore's law equivalent of ∼40%/annum. A necessary enabler to a high areal density is the HMS, or the distance from the bottom of the read sensor on the flying head to the top of the magnetic medium on the rotating disk. This paper describes the various components of the HMS and various scenarios and challenges on how to achieve a goal of 4.0-4.5 nm for the 4 Tbit/in 2 density point. Special considerations will also be given to the implication of disruptive technologies such as sealing the drive in an inert atmosphere and novel recording schemes such as bit patterned media and heat assisted magnetic recording.

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

“…2 , the distance between the magnetic sensors in the heads and the magnetic media on the disks, which is typically around 80 to 100 Å , has to be reduced to around 65 to 89 Å . 11,12 Consequently, the thickness of the protective DLC:H films which is the main contributor to the spacing needs to decrease from its typical value of 20 to 30 Å today to only 20 to 25 Å . 11,12 Since these films are employed to fulfill different functions on the disks, such as providing a barrier against corrosion, planarization, durability, and protection against contamination, it is of technological and scientific interest to understand whether ultra-thin DLC:H films (thickness below 50 Å ) can retain the well-characterized physical properties, composition and microstructure of thicker films (thickness around 200 Å ) and whether they have a non-uniform crosssectional structure.…”

Laser induced spin precession in highly anisotropic granular L1 FePt

“…Carbon does not coalesce with FePt hence forming physically isolated and exchange decoupled grains of roughly 7 nm diameter and a grain size distribution of r ¼ 16%. 11 The magnetic layer is capped by a 3 nm thick protective diamond like carbon (DLC) overcoat, 16 allowing for optical access.…”

Giant Magnetoresistance Sensors Based on Ferrite Material and Its Applications

“…Figure 10. Trend of the increase of areal density of HDD and flash disk to the year of production [33].…”