October 16, 2007 The exponential growth of digital storage capacity continues unabated with news that Hitachi has developed recording heads up to 2,000 times smaller than the width of an average human hair – a nanotechnology breakthrough that is expected to quadruple current storage capacity limits to four terabytes (TB) on a desktop hard drive and one TB on a notebook hard drive.
Hitachi, Ltd. and Hitachi Global Storage Technologies have claimed the world’s smallest read-head technology for hard disk drives with the announcement, reduced existing by more than a factor of two to achieve new heads in the 30-50 nanometer (nm) range.
A key technical challenge in the development of this technology was to overcome problems associated with electronic noise. The smaller the HDD, the more problems there are in reading the information – smaller recording heads mean increased electrical resistance and increased noise, limiting the head’s ability to correctly read the data signal.
The current Tunnel Magneto-Resistance head (TMR) heads used for this purpose are problematic for recording densities below 500 Gb/sq. in., so a low-resistance, small-output alternative known as current perpendicular-to-the-plane giant magnetoresistive (CPP-GMR) technology that has the potential to read HDDs as dense as one terabit per square inch (Tb/sq. in.) has been used by Hitachi as the basis for the new heads.
Hitachi’s advancements to this technology has resulted in a significant improvement in signal-to-noise ratio. For heads with track widths of 30nm to 50nm, S/N ratios of 30 decibels (dB) and 40 dB, respectively, were recently achieved with the heads co-developed at Hitachi GST’s San Jose Research Center and Hitachi, Ltd.’s Central Research Laboratory in Japan.
How far have we come? A comparison between the latest technology and the first HDD recording head – which debuted in 1956 in the RAMAC hard drive – shows a size reduction by a staggering factor of 40,000.
Incidentally, the 1988 discovery of the GMR effect by France's Albert Fert and Germany's Peter Gruenberg was recently recognized with a Nobel Prize for physics.
Hitachi is presenting these achievements at the 8th Perpendicular Magnetic Recording Conference (PMRC 2007) currently being held at the Tokyo International Forum in Japan.
Hitachi’s new technology is expected to be implemented in shipping products in 2009 and reach its full potential in 2011.