In two papers published in the April 11 issue of Science, IBM Fellow Stuart Parkin and colleagues at the IBM Almaden Research Center in San Jose describe both the fundamentals of a technology dubbed "racetrack" memory as well as a milestone in that technology. This milestone could lead to electronic devices capable of storing far more data in the same amount of space than is possible today, with lightning-fast boot times, far lower cost and unprecedented stability and durability.
Within the next ten years, racetrack memory, so named because the data "races" around the wire "track," could lead to solid state electronic devices - with no moving parts, and therefore more durable - capable of holding far more data in the same amount of space than is possible today. For example, this technology could enable a handheld device such as an mp3 player to store around 500,000 songs or around 3,500 movies - 100 times more than is possible today - with far lower cost and power consumption. The devices would not only store vastly more information in the same space, but also require much less power and generate much less heat, and be practically unbreakable; the result: massive amounts of personal storage that could run on a single battery for weeks at a time and last for decades.
For nearly fifty years, scientists have explored the possibility of storing information in magnetic domain walls, which are the boundaries between magnetic regions or "domains" in magnetic materials. Until now, manipulating domain walls was expensive, complex, and used significant power to generate the fields necessary to do so. In the paper describing their milestone, "Current Controlled Magnetic Domain-Wall Nanowire Shift Register," Dr. Parkin and his team describe how this long-standing obstacle can be overcome by taking advantage of the interaction of spin polarized current with magnetization in the domain walls; this results in a spin transfer torque on the domain wall, causing it to move. The use of spin momentum transfer considerably simplifies the memory device since the current is passed directly across the domain wall without the need for any additional field generators.
