Hitachi has developed what it claims is the world's smallest read-head technology for hard disk drives.

The breakthrough is expected to quadruple current storage capacity to 4TB on a desktop hard drive and 1TB on a notebook hard drive.

Researchers at the electronics giant have successfully reduced existing recording heads to the 30-50nm range, up to 2,000 times smaller than the width of a human hair.

Hitachi expects to ship the Current Perpendicular-to-the-Plane Giant Magneto-Resistive (CPP-GMR) technology in 2009 and reach full stride in 2011.

Hiroaki Odawara, research director at Hitachi's Storage Technology Research Centre, said: "This is an achievement for consumers as much as it is for Hitachi, as it will fuel the growth of the 'Terabyte Era' of storage."

Hitachi believes that CPP-GMR heads will enable hard drive recording densities of 500Gb to 1Tb per square inch, a quadrupling of today's highest areal densities.

The company delivered the industry's first terabyte hard drive earlier this year with 148Gb per square inch, while the highest areal density Hitachi products shipping today are in the 200Gb per square inch range.

These products use existing tunnel-magneto-resistive head technology.

A high electron-spin-scattering magnetic film material was used in the CPP-GMR layer to increase the signal output from the head, along with a new technology for damage-free fine patterning and noise suppression.

As a result, the signal-to-noise ratio, an important factor in determining the performance of a head, was dramatically improved.

Hitachi will present its achievements at the eighth Perpendicular Magnetic Recording Conference from 15-17 October at the Tokyo International Forum in Japan.

Albert Fert and Peter Grünberg were awarded the Nobel Prize for Physics this year for their discovery of Giant Magnetoresistance (GMR) in 1988, which revolutionised the technology used in hard drives today.