Magnetomechanical Four-State Memory
With current non-volatile memory technology approaching intrinsic storage density limits, new data storage technologies are under development. Probe-based storage systems provide alternatives to conventional mass storage technologies. Ni-Mn-Ga, a ferromagnetic shape memory alloy (FSMA), is proposed as a medium for multi-bit storage using scanning probe microscopy (SPM) techniques. Local modifications of the magnetic stray field were achieved using nanoindentation. Magnetic poles collect within the indentation, which is leveraged to control the magnetic stray field for the patterning of magnetic information. Four magnetic-based memory states are possible due to magnetic field or stress-induced twin rearrangement along two crystal orientations, each with two possible magnetic orientations.
Watson, Chad S.; Hollar, Courtney; Anderson, Kimball; Knowlton, William B.; and Müllner, Peter. (2013). "Magnetomechanical Four-State Memory". Advanced Functional Materials, 23(32), 3995-4001. http://dx.doi.org/10.1002/adfm.201203015