Racetrack Memory: a high capacity, high performance, non-volatile spintronic memory

Abstract

Racetrack Memory is a novel, emerging spintronic memory whose fundamental principle is the movement of the encoded digital data, in the form of chiral magnetic domain walls, along nanoscopic magnetic racetracks, to reading and writing devices that are built into the racetrack itself. Thus, a single device - the racetrack - accommodates multiple bits, perhaps as many as one hundred or more, thereby allowing for massive data capacities that rival those of magnetic disk drives or today's solid-state memories. The domain walls are moved by nanosecond current pulses that are converted into spin-polarized currents via volume spin dependent scattering, or into pure spin currents via spin-orbit coupling derived phenomena, most importantly the spin Hall effect. Recent discoveries that have shown highly efficient current induced motion of chiral domain walls with speeds of ∼1 km/s or higher in synthetic antiferromagnetic racetracks make possible high performance racetrack memories. Of special interest is a one-domain wall racetrack memory that has the potential to operate at deep sub-nanosecond speeds, and, thereby, could supplant SRAM and, moreover, be much denser than today's or prospective SRAM and, in addition, is non-volatile. There is no other memory technology that has the enormous potential of Racetrack Memory.