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Magnetic Microchips
Mr_Ceebs writes, "Looking at the BBC today I find a new Magnetic rather than electronic chip type. The design can raise the number of chips per cm by a factor of about 1000, with the preliminary stages of the technology. For all devices this would mean the demise of the large battery pack. " H : This is a follow-on to this morning's story on moldable magnets.
okay, i'm figuring that i'm the only one posting that actually has experience in fabricating and measuring magnetic nanostructures so here goes:
the BBC article is typically crap. what happens is someone from cambridge or oxford needs PR so they call up the press and tell them how many transistors they can squeeze onto the head of a pin. in the end, there's really no science in the article and, for those astute readers out there, in this particular article they don't make much mention of how these things work, what material they are using, what temperature they've demonstrated these things at, etc.
Typically, these estimates on transistor density are made when the lab produces a prototype with the active elements within a certain area. by no means does this mean that they've constructed a 5.5 billion density device that works.
they don't tell you what the mechanism is-- tunneling magnetoresistance (TMR) or spin-diffusion/accumulation ('Johnson spin transistors'), however the switching speeds are estimated to be much faster than conventional semiconductor devices (there's some argument for this in IEEE spectrum from about 5 yrs back that i can't remember).
reliability?
they have omitted mention of the gate mechanism here. how do they plan on switching these things individually? telepathy? if they are using EM fields generated by wires, then there is the inevitable heating to deal with. what material are they using? what's the curie temperature? how hot do they expect these things to get? hey wait! there's no size bar on that pretty picture of the magnets!?
blah blah blah.
BAD JOURNALISM from the BBC.
i may be a jerk about this, but i think everyone's getting a bit caught up in the hype without enough data and it's irritating as a scientist.