(magnetic storage presentations)
Research and Development Center
1 Komukai, Toshiba-cho
Saiwai-ku, Kawasaki 210-8582, Japan
Date Visited: 12 March 1998
Toshiba is a diversified company with more than $44 billion in sales. More than half of that is in the information/communications systems and electronic devices segment. In the computer marketplace, it is especially strong in laptop computers, where it is the industry leader. Toshiba has a major market share in liquid crystal displays, 2.5 inch HDDs, and optical storage devices for the portable market.
Toshiba R&D Center is a world-class facility, with more than a thousand researchers. It is just one of 15 Toshiba labs worldwide.
After an overview presentation by Mr. Nakatsuka, and a series of summary presentations by the U.S. panelists, the panel received presentations on spin-dependent tunneling, contact recording head technology, and GMR head technology. The spin-dependent tunneling work by Dr. K. Inomata is aimed at increasing head sensitivity by increasing the delta R and at improving reliability by reducing the likelihood of pinhole shorts. To this end, Toshiba researchers use a double gap resonant tunneling geometry. The results are very impressive, though the impedance of 10,000 ohms for a one square micron device is still too high for high data rate applications.
The contact recording work by Dr. Y. Kubota is aimed at producing a head/disk interface with less than 10 nm spacing, which will be needed for ultra-high density magnetic recording. The approach is conceptually related to the Tripad technology developed by Readrite Corporation. It remains to be seen whether the resulting low contact pressure will allow an acceptable wear rate and lifetime. It may turn out that this interface is practical for low speed applications only.
The third Toshiba talk by, M. Sahashi, was on a suite of technology improvements that allow the company to make a high performance, high output bottom type spin valve using <111> oriented IrMn antiferromagnetic pinning layers and CoFe/Cu/CoFe GMR layers. This shows that Toshiba is at the leading edge in spin valve design and materials. Detailed discussion of this topic does not fit the five to 15 year pre-competitive charter of this study, but the WTEC panelists found it impressive.
The panel received a visually stunning demonstration of high resolution DVD technology at the Toshiba Science Institute Theater.
Toshiba maintains one of Japan's strongest research organizations in advanced data storage. In the magnetic recording area, its roadmap seems to correspond to that in the United States, with the possible exception of an earlier approach to contact recording than is expected here. Toshiba's work on spin tunneling has the potential of very large efficiencies, but cannot be fully evaluated at high data rates until a method of lowering the impedance is found, or until a high impedance amplifier can be incorporated into the sensor itself.