Racetrack memory

Racetrack memory or domain-wall memory (DWM) is an experimental non-volatile memory device under development at IBM's Almaden Research Center by a team led by physicist Stuart Parkin. In early 2008, a 3-bit version was successfully demonstrated. If it were to be developed successfully, racetrack would offer storage density higher than comparable solid-state memory devices like flash memory and similar to conventional disk drives, with higher read/write performance.

Racetrack memory uses a spin-coherent electric current to move magnetic domains along a nanoscopic permalloy wire about 200 nm across and 100 nm thick. As current is passed through the wire, the domains pass by magnetic read/write heads positioned near the wire, which alter the domains to record patterns of bits. A racetrack memory device is made up of many such wires and read/write elements. In general operational concept, racetrack memory is similar to the earlier bubble memory of the 1960s and 1970s. Delay line memory, such as mercury delay lines of the 1940s and 1950s, are a still-earlier form of similar technology, as used in the UNIVAC and EDSAC computers. Like bubble memory, racetrack memory uses electrical currents to "push" a sequence of magnetic domains through a substrate and past read/write elements. Improvements in magnetic detection capabilities, based on the development of spintronic magnetoresistive sensors, allow the use of much smaller magnetic domains to provide far higher bit densities.

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