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Spotlight on Optics


  • August 2012

Optics InfoBase > Spotlight on Optics > Integrated head design using a nanobeak antenna for thermally assisted magnetic recording

Integrated head design using a nanobeak antenna for thermally assisted magnetic recording

Published in Optics Express, Vol. 20 Issue 17, pp.18946-18954 (2012)
by Takuya Matsumoto, Fumiko Akagi, Masafumi Mochizuki, Harukazu Miyamoto, and Barry Stipe

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Spotlight summary: With the goal of overcoming the superparamagnetic limit in magnetic data storage, many researchers have focused on the long-known approach of recording data on hard magnetic media with the assistance of laser heating to momentarily soften the material, a technique known as heat (thermal, or energy) -assisted magnetic recording (HAMR, TAMR, and EAMR). This scheme can potentially help to advance further the magnetic storage capacity by one to two orders of magnitude. It requires the use of nano-optics to concentrate an assisting laser beam down to nanoscale in order to create a sub-nanosecond local temperature of 700 K or higher in the medium around its Curie temperature. There has been much progress in the field towards future mass production, and many efforts have been made to achieve high process reliability and manufacturing scalability following successful laboratory demonstrations.

In response to this revolutionary shift in magnetic data storage applications, the authors of this Optics Express paper present a numerical study of an integrated thin-film TAMR recording head and medium design, which has the potential of achieving impressively high efficiency of light delivery and density of magnetic recording. In their work, they used a modified nanobeak antenna as a near-field optical transducer to thermally activate the magnetic medium and spatially define a nanoscale spot near the magnetic recording head. A thin-film waveguide was placed at the near field of the optical transducer for light delivery purposes, and a wing structure was added to the antenna to further enhance the near-field optical coupling. Based on their calculations, the authors estimate that about 8% of the total optical power (a few milliwatts) in the waveguide can be absorbed by the medium to generate a required temperature rise of 350 K, and they expect this head design to achieve an areal density of 2.5 Tb/in2 according to their magnetic read/write simulations. Despite of the exciting advantages promised, many mechanical, thermal, and material issues have to be tackled before this approach can succeed in real world, which calls for fundamental research breakthroughs to overcome the remaining hurdles.

--Liang Pan

Technical Division: Information Acquisition, Processing, and Display
ToC Category: Optical Data Storage
OCIS Codes: (230.3810) Optical devices : Magneto-optic systems
(210.4245) Optical data storage : Near-field optical recording
(250.5403) Optoelectronics : Plasmonics

Posted on August 24, 2012

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