into satellites and not handsets.
Where the IBM team has gone further is in building a small memory; Ono's team was just demonstrating the ability to use current to push the magnetic domains around. Parkin's memory is even more power hungry: 200 million amps per square centimetre. Which kind of makes a nonsense of IBM PR's claim that this type of memory is going to consume less power than today's devices, or even disk drives. And the bits are big. The wires are only a couple of hundred nanometres across, but the bits have to have 2000nm separating them to stop them running into each other and disappearing – another knotty problem with this kind of memory. That makes the size of each bit considerably larger than today's flash memories.
There is a way round the density problem: you can stack layers of wires on top of each other – the wires are are less than 10nm thick. That is the design that Cowburn favours. Not only does it improve density, if you read the layers in parallel, you could potentially get very high datarates out of these devices even if you read the bits out quite slowly – a technique that should reduce power consumption. IBM seems to favour a vertical configuration so the read elements are all on the bottom of the chip. Strings like this have yet to be made but Toshiba has pursued a similar idea with a flash memory it unveiled at last year's VLSI Symposium.
Ono's team has worked on the energy problem, identifying an alternative to the regular nickel-iron wires normally used in this kind of research that can work at room temperature – another Japanese team slashed the energy needed by three orders of magnitude a few years back, but the device needs to be cooled artificially. The cobalt-platinum alloy Ono's group used has a built-in magnetic field which should improve on the way these nanowires behave. However, according the paper, the current needed is still in that 100 million range.