Tuesday, October 9, 2007

Practical Nobel Prize

It is about time (said even though I am a theorist)!

This is the time during the semester that we get to magnetism and the physics of important practical phenomena such as the Hall Effect (which is used to measure magnetic field strength, characterize the properties of semi-conductors, and, in its quantum version, establish a standard voltage). I always point out to my class that the mundane physics of such things as magnetic disk drives, like the mundane chemistry and physics of batteries, is as crucial to modern technology as the silicon chip ... and much more important to the functioning of our economy (or military) than electro-weak unification and other cool subjects of high energy particle theory that got all the press back when this work was published.

It is great to see a practical discovery related to magnetic data storage rewarded with a Nobel Prize.

This year's Nobel Prize in Physics was given to Albert Fert and Peter Gr├╝nberg for discovery of the Giant MagnetoResistance effect. This effect is used to read the tiny changes in magnetic field that signal the difference between a zero and a one when data are stored on a magnetic disk storage device. It has made possible the rapid (to someone as old as I am, spectacular) decrease in size of computer disk drives. For once, the media are not exaggerating when they say that this recent (late 1980s) discovery from basic research made the iPod possible.

One simple example: We own a half terabyte disk drive that is smaller than a Harry Potter novel. That is 500 gigabytes, for those who don't yet know the nomenclature, essential to backup all the data generated by a digital camera. A bit over 20 years ago, just a few years before the GMR discover was made, I used a computer system that had a terabyte (1000 gigabytes) of storage mixed between disk and automatic tape drives. That terabyte of storage took up a space larger than our house.

I won't elaborate on the physics, which is way outside of my personal expertise in nuclear physics, because general information on the discovery, as well as links to pdf files suitable for the general reader as well as physicists, can be found in the press release from the Nobel committee.

Addenda:
A comment over at Uncertain Principles included a link to an IBM corp article on R and D that puts GMR to work.

When talking about this to my physics class, I remembered that a computer I used for my thesis research had a 1 megabyte (0.001 gigabyte) disk for key programs (operating system, compiler, device drivers) that was a beautifully polished platter about 2 feet in diameter. A factor of a million in data with a reduction in volume of maybe a factor of 10, not to mention an increase in reliability and a drop in cost by what is probably a factor of a million in current dollars.

I also pointed out in the lab how important it is to have reliable contemporaneous lab notebooks in ink to help document your independent discovery that might lead to a valuable patent if not a Nobel Prize.

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