2 physicists win Nobel for work in computers

German and Frenchman share prize for breakthrough in nanotechnology

October 10, 2007|By Dennis O'Brien | Dennis O'Brien,Sun reporter

Now you know whom to thank for that iPod.

Credit the French and German physicists who won the Nobel Prize yesterday for discovering the small magnetic twist that made it possible to read ever-smaller bits of magnetic information from computer hard drives - paving the way for today's lightweight laptops and sleek portable music players.

Albert Fert, 69, a professor at the University of Paris-Sud, and Peter Gruenberg, 68, of the German Research Center in Juelich, will share the $1.5 million prize from the Royal Swedish Academy of Sciences, which praised the achievement as one of "the first real applications of the promising field of nanotechnology."

Early computers were larger and slower than today's machines, and the hard drives they used to store information - based on spinning magnetic platters - took up far more space and were far more expensive than they are today.

As computers became faster and computer drives became smaller, more sensitive read-out techniques were required. Experts say Fert and Gruenberg's discovery is a major reason that today's drives have 100,000 times more storage capacity than the disks of 20 or 30 years ago.

"They discovered something completely new in physics," said Chia-Ling Chien, a professor and director of the Material Research Science and Engineering Center at the Johns Hopkins University.

As more and more technologies based on the discovery hit the market, Chien said, he predicted to colleagues a few years ago that the pair would win the Nobel. "The impact is just too great," he said.

The Nobel panel awarded the prize for work performed in 1988. Working separately, Gruenberg sandwiched two or three layers of nonmagnetic chromium between two slices of magnetic iron, while Fert created the same kind of thin, multilayered magnet sandwich from 30 alternating iron and chromium sheets.

Both found a startling electrical property: By altering the thickness of the nonmagnetic sheets, they could alter the electrical resistance of the magnetic field and detect tiny changes in it.

Technically, the discovery was known as "spin dependent scattering in a multilayer magnetic field." Fert called the phenomenon "Giant Magnetoresistance" because it demonstrated a way to create relatively large changes in the electrical current of a magnetic field. Since then, the term has been shortened to GMR.

The information that a computer processes is stored in binary code - ones and zeroes. On a computer's hard disk, magnetic material can be broken up into tiny domains that can be made to correspond to those ones and zeroes. To read and write information, magnetic heads travel across the surface of the spinning disk.

By the early 1990s, computer drives made of nickel iron alloy strips had become the state of the art. But even they could detect only 1 percent of the changes in electrical resistance brought on by changes in a magnetic field, said Romel Gomez, a University of Maryland professor of computer and electrical engineering.

The pair's discovery led to technology that allows for the detection of 80 percent of the changes in the electrical resistance, he said.

"Their work spurred a lot of this incredible reduction in the size of the bits that can be stored on hard disks," Gomez said.

Since it was first mass-produced in 1997, Giant Magnetoresistance technology has become standard equipment in read-out heads that scan disks in laptops, many mobile phones, audio devices and any portable or desktop computers that use magnetic drives to store information.

"It's in your iPod, TiVO, all these things are possible because of the work they did," said Julie Borchers, a physicist at the National Institute of Standards and Technology in Gaithersburg. "It's had a huge impact on the field of magnetic storage."

Yesterday's announcement was the second Nobel awarded this week. Three scientists shared the Nobel in Medicine or Physiology on Monday for their work on mouse genetics.

dennis.obrien@baltsun.com

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