Finally, they’ve figured out something that neural systems have capitalized on for a while: Using all 3 dimensions. Check it out:
And a nice semi-technical discussion from EE Times on current 2D RAM and how racetrack memory takes advantage of 3 dimensions. A key concept here (and an old one, see bubble memory below) is “massless motion”: Applying a current to a tape moves the magnetic domains along in a similar manner to mechanically moving the tape.
On the macro scale, a similar type of memory called bubble memory was available up to the early 1980s when it was replaced with hard disks. Seems like high speed (pushing the correct magnetic portion of the nanowire to the read head) and doing so without excessive current are what really make this a viable technology now.