Bit-patterned media (BPM) for magnetic recording provides a route to thermally stable data recording at >1 Tb/in2 and circumvents many of the challenges associated with extending conventional granular media technology. Instead of recording a bit on an ensemble of random grains, BPM comprises a well-ordered array of lithographically patterned isolated magnetic islands, each of which stores 1 bit. Fabrication of BPM is viewed as the greatest challenge for its commercialization. In this paper, we describe a BPM fabrication method that combines rotary-stage e-beam lithography, directed self-assembly of block copolymers, self-aligned double patterning, nanoimprint lithography, and ion milling to generate BPM based on CoCrPt alloy materials at densities up to 1.6 Td/in2. This combination of novel fabrication technologies achieves feature sizes of <;10 nm, which is significantly smaller than what conventional nanofabrication methods used in semiconductor manufacturing can achieve. In contrast to earlier work that used hexagonal arrays of round islands, our latest approach creates BPM with rectangular bit cells, which are advantageous for the integration of BPM with existing hard disk drive technology. The advantages of rectangular bits are analyzed from a theoretical and modeling point of view, and system integration requirements, such as provision of servo patterns, implementation of write synchronization, and providing for a stable head-disk interface, are addressed in the context of experimental results. Optimization of magnetic alloy materials for thermal stability, writeability, and tight switching field distribution is discussed, and a new method for growing BPM islands from a specially patterned underlayer-referred to as templated growth-is presented. New recording results at 1.6 Td/in2 (roughly equivalent to 1.3 Tb/in2) demonstrate a raw error rate <;10-2, which is consistent with the recording system requirements of modern hard drives. Extendibility of BPM to higher densities and its eventual combination with energy-assisted recording are explored.

Hard disk drives are packed with increasingly higher density in modern data storage enclosures and systems. This may impose some risks to the system dynamic performances if the system is not well designed. For example, the hard disk drive (HDD) read and write (R/W) performance will be degraded more due to higher mechanical cross-talk as there are more and closely arranged HDDs in the system. Secondary, the more HDDs packed in a storage enclosure, the more mass the system has. This lowers the system modal frequencies and likely affects its dynamic performances, such as non-operational shock behavior during shipping and handling of the system and HDD operational vibration due to external vibrations. In this paper, we will study both non-operational shock and operational vibration using a state of the art HGST storage enclosure which has the highest HDD volumetric density packaged in any enclosure on the market.

Heat assisted magnetic recording (HAMR) and slim mobile hard disk drives (HDD) are being developed parallelly to maintain cost advantage over the solid state drive. Operational shock and non-operational shock capabilities are seriously challenged for the slim HDDs due to reduced stiffness (thickness). It is worse for slim HAMR drives due to additional laser diode (LD) and other necessities being added on slider. Shock tests are part of the key performance matrices that must be passed in HDD reliability tests, and the concerns for HAMR mobile drives are, (1) slider lift-off G-level degradation during op-shock, and (2) LD back-to-back hitting during non-operational shock. We studied a few potential HAMR HGA designs, also analyzed a design that improves drive op-shock performances.

We report on the fabrication of 1 Tdot/in2 bit patterned media with high coercivity (HC) and narrow intrinsic switching field distribution (iSFD) based on nanoimprint from a master pattern formed by e-beam guided block copolymer assembly onto a carbon hard mask and subsequent pattern transfer via etching into a thin CoCrPt perpendicular anisotropy recording layer. We demonstrate that an additional vacuum annealing step after pattern transfer into the CoCrPt layer and after Carbon hard mask removal not only yields recovery from undesired damage of the island edges, but actually transforms the islands into a magnetically more favorable compositional phase with higher HC, lower iSFD/HC, and three-fold increased thermal stability. Energy filtered transmission electron microscopy analysis reveals that the diffusion of Cr from the island cores to the periphery of the islands during post-annealing is responsible for the transformation of the magnetic bits into a more stable state.

Disk drives are packed at ever dense arrangement in a modern data storage system, internal and external mechanical disturbances can have a great effect to disk drive's read and write performances. The VCM torque generated during seeking affects its own as well as neighboring drives head position. In this study, we modeled a storage box with multiple HDDs installed to obtain mechanical system transfer function. The mechanical excitation is characterized by VCM torque, and HDD operational vibration behaviors on linear and rotational shakers are measured. A system level hybrid method predicting HDD head position error in a data storage box is described, and both analytical and measured results will be presented.

As recording area density increases, magnetic recording is approaching near contact regime. Disk deformations, both tangential and circumferential, affect magnetic head flight height (FH) significantly at this FH range, and it becomes increasingly important to magnetic reading and writing performances. Variation in manufacturing process, mechanical tolerance as well as design itself can affect disk deformation greatly. In this presentation, we present a few disk pack design improvements to minimize disk coning and disk crown. The designs are able to achieve consistent disk deformation even under significant manufacturing tolerances.