Heat assisted magnetic recording (HAMR) is one of the leading technologies to extend magnetic storage. Significant progress has been achieved in head and media fabrication [M. Seigler et al., IEEE Trans. Magn. 44, 119 (2008); Y. Peng et al., TMRC, Seagate Research, 2008], resulting in a basic technology demonstration (C. Hardie et al., ODS Conference Proceedings, 2008) of HAMR. Both field and field-gradient limitations of a conventional perpendicular recording are overcome by engineering the thermal profile (notably the gradient) and recording at a temperature near Tc (thus requiring a smaller head field). We have used a micromagnetic recording model to study the effect of thermal and field-gradient alignment in HAMR by varying the separation between the thermal spot and the leading edge of the head field. The output of the recording model includes transition jitter, which is based on Monte Carlo simulations of isolated transitions. We use a realistic granular medium with HK∼50–80 kOe and a grain size of ∼2.5–6 nm that covers a broad range of HAMR media parameters. The model indicates that HAMR can achieve >1 Tbyte/in.2 using a grain size of 6 nm and is scalable to >4 Tbyte/in.2 on a granular media by careful alignment of the thermal and magnetic field gradients.

Heat-assisted magnetic recording is a promising approach for enabling large increases in the storage density of hard disk drives. A laser is used to momentarily heat the recording area of the medium to reduce its coercivity below that of the applied magnetic field from the recording head. in such a system, the recording materials have a very high magnetic anisotropy, which is essential for the thermal stability of the magnetization of the extremely small grains in the medium. This technology involves new recording physics, new approaches to near field optics, a recording head that integrates optics and magnetics, new recording materials, lubricants that can withstand extremely high temperatures, and new approaches to the recording channel design. This paper surveys the challenges for this technology and the progress that has been made in addressing them.

Heat-assisted magnetic recording (HAMR) has emerged in the past few years as one of the leading candidates to carry magnetic data storage toward areal densities of 1 Tb/in/sup 2/ and perhaps well beyond. The use of thermal-assistance for writing very high anisotropy magnetic media is a natural means of continuing the decades-old paradigm for scaling upward the storage density capability of particulate magnetic films. This approach appears to be fully compatible with extension of the performance of perpendicular recording well beyond its expected limits using ambient temperature recording. Recent developments indicate that HAMR may take advantage of thermal energy imparted in the recording process to achieve extremely fast magnetic switching without the need for inordinately high writing head fields, thus enabling performance advances.

Heat-assisted magnetic recording (HAMR), also known as hybrid recording, has been, proposed to enable storage densities greater than 1 Tb/in(2) in hard disc drives while circumventing the superparamagnetic limit. Light is delivered in the near field to the recording medium to heat just the spot which is to be recorded. Techniques based on apertures, antennas, waveguides,, and solid immersion lenses have been suggested for delivering substantial amounts of optical power into subwavelength spots in the near field. A practical transducer for HAMR may require a combination of techniques.

The merging of concepts from magnetic and optical recording technology is now considered an important approach for the continuation of the forty-five year upward march of areal density performance in rigid disk drives (RDD) and other recording systems. Hybrid recording has been proposed in many forms, but here we discuss architectures appropriate for the anticipated thrust of RDD toward 1 Tb/in2 and beyond. At these extreme areal densities, many novel technologies must be combined for the performance of thermomagnetic recording consistent with the exacting requirements of RDD. The design of media to support this technology at the required densities will demand significant extensions from past trends into realms that accommodate use of elevated temperatures and compatibility with novel sources of near-field (NF) electromagnetic (EM) energy. We report thermomagnetic recording simulations which illustrate how the recording physics are centrally related to the interplay of optical, thermal, and magnetic phenomena

We have carried out a combined experimental and computer simulation study to specify and identify candidate films to support high areal density, thermally-assisted magnetic recording. The motivation of this work is to utilize the enhanced writability of very high coercivity materials that thermal assistance can provide. Media with high coercivity (and anisotropy Ku) are known to be essential to achieve a sufficiently high ratio of KuV/kBT necessary to maintain magnetic stability at temperature T in media switching units (grains; single domains) of volume V. Nominally, we expect V ∝ D−3/2, where D is the medium bit density per unit area in recording. A micromagnetic recording simulation tool with a capability of representing realistic grain size distributions, temperature-dependent magnetic properties, and spatially-varying imposed temperature distributions was employed to study the interplay of thermal and magnetic field gradients in the recording process. In addition, a simple LLG-based thermomagnetic switching model supplemented the micromagnetics model. We fabricated improved Co/X multilayer media for recording evaluation, and performed standard materials characterization.

Optical data storage media for bit-wise recording of a microhologram using an incident radiation at a wavelength of about 405 nm are provided. The optical storage medium includes (a) a non-photopolymer polymer matrix; (b) a non-linear sensitizer comprising a phenylethynyl platinum complex, wherein the non-linear sensitizer is capable of triplet-triplet energy transfer from an upper triplet state (Tn) of the non-linear sensitizer to a lower triplet state (T1) of a reactant, wherein “n” is an integer greater than 1; and (c) a reactant capable of undergoing a chemical change upon the triplet-triplet energy transfer from the non-linear sensitizer, thereby causing a refractive index change in the medium to record the microhologram.

Direct overwrite (DOW) at 2X operating densities has been demonstrated utilizing an IBM 2X drive and exchange coupled multilayered media. To generate the writing waveforms required for DOW, modifications of the laser driver electronics were implemented. The drive was integrated into a test bed to study the light intensity modulation direct overwrite media writing and overwriting characteristics. In this paper, we show that utilizing simple write waveforms consisting of PHi superimposed on a pedestal power, does not permit the attainment of satisfactory figure of merits (FOMs). We show that by modifying the write waveform we increase the temperature gradients that precisely define the written marks. Consequently, it is possible to achieve good FOMs even at OD conditions, and this is done by implementing straightforward modifications to the laser drive electronics of an IBM 2X drive.

Interchangeability standards for writable optical data storage media allow considerable range in the design of media and optical devices. Naturally, the most reliable system performance occurs when the media design is made fully compatible with the particular characteristics of the drive. This paper treats design of the thin film structure of magneto-optical media for optimum readout compatibility with the drive. The methodology centers on maximization of system signal-to-noise ratio (SNR) under general conditions of system noise composition. We present simple models for the behavior of the various noise components in optical disk drives-medium, laser, shot, electronic. The total system noise model is supplied with relative component weights derived from experimental noise decomposition measurements on the physical system (drive or tester). By changing the relative weights of system noise components, one can readily identity optimum medium designs under different conditions of noise dominance

An experimental and computer simulation study of the effect of writing laser pulse rise and fall time on magneto-optic recording performance was performed. We find that reducing the rise/fall time improves the writing efficiency and power margins, as well as improving peak shift and jitter, leading to improved detection margins.