All-Magnetic, Nonvolatile, Addressable Chainlink Memory

MRAM has come into the spotlight as a potential candidate for universal memory. In this paper, we introduce chainlink, a concept for all-magnetic, nonvolatile memory. Two conductive paths form a chain through which data shifts. Each path is composed of short magnetic nanowires, or links, that store magnetization representing data bits. Data is moved along a link by spin-transfer torque and propagates to an adjacent, electrically-insulated link in the opposite path via magnetic coupling. Distinct phases of current pulses are applied to the paths to ensure the operation is fully digital and collision of data tokens is avoided. Multiple shift registers can be addressed with all magnetic elements; no transistors are required to access each bitcell. Micromagnetic and SPICE simulation of bit propagation and architecture elements demonstrate successful operation with 30 MA/cm², 2 ns current pulses.