Tokyo Tech News
September 30, 2010
Shigeki Nakagawa at the Department of Physical Electronics and collaborators at Hitachi Maxell have succeeded in producing magnetic tape memory with an astounding world record areal density of 45.0 Gb/in2 (Giga-bits/square inch) by a unique facing targets sputtering method (Fig.1) for depositing thin films of granular magnetic particles.
These results would enable over 50 terabyte capacity per a tape cartridge—more than 33 times the capacity of current technology.
The key development was the deposition of vertically orientated magnetic nanostructures (magnetic cores and non-magnetic periphery) with diameters of less than 10 nm by the facing targets sputtering method. Conventional methods employ coating of particles onto tapes, but it is not possible to produce magnetic particles with diameters of less than 10 nm by this approach.
The facing targets sputtering method—which was invented at Tokyo Institute of Technology—enables the deposition of magnetic films on thin plastic substrates at room temperature and importantly, without damaging the films. The distinct feature of the facing targets sputtering method is that the substrates are not located inside the plasma, as is the case with conventional magnetron sputtering.
The researchers plan to take these results from the lab to the market with financial support from JST research grants.
Fig. 1: Facing targets sputtering film to fabricate multilayers for granular type tape media
Fig. 2: Transmission electron microscope views of granular type perpendicular magnetic recording tape media prepared by facing targets sputtering system.
Graduate School of Science and Engineering Physical Electronics