”Instead of an electron being there or not there in the gate of a transistor—basically two pieces of information—think about an electron being able to hold a million pieces of information,” says David Awschalom, a physicist at the University of California at Santa Barbara who specializes in the development of magnetic semiconductors. In addition to being much faster, spintronics processors could be much smaller than present-day processors.
To incorporate spin technology into processors, however, researchers need to surmount the problem of making spin-polarized currents flow through semiconductors at room temperature. This has proved to be a perennial bugaboo because most semiconductor materials that have been tried function ideally at temperatures below -120 °C. But as surrounding temperatures rise, they lose their special magnetic properties, making them impractical for use in electronics and other consumer products.
A team led by Jagadeesh Moodera at MIT’s Francis Bitter Magnet Laboratory has inched closer to this goal by developing a magnetic material that can transmit spin currents without being chilled [see photograph, ”Ambience”]. Consisting of indium oxide with trace amounts of magnetic chromium, the team's device rests atop a conventional silicon semiconductor and polarizes the spin of incoming electrons, which then flow directly into the chip. After traveling through the doped indium-oxide semiconductor, the spin-polarized electrons are read by a spin detector at the other end of the circuit, which determines the electrons' spin by accelerating them to high energies and scattering them (electrons of opposing spin states always scatter in different directions).
The indium-chromium mixture fulfills its function perfectly because when combined, these substances contain periodic ”gaps” in their molecular arrangement where oxygen atoms are missing. By modifying the character and extent of these gaps at the atomic level, Moodera can fine-tune the material's magnetic behavior to an unprecedented degree.
Stuart Wolf, a physicist at the University of Virginia in Charlottesville who has been involved in spintronics research for over a decade, describes Moodera's results as ”extremely encouraging....There have been similar reports of magnetism in other [semiconductor] substances, but the evidence reported in these earlier papers was not totally convincing,” he says. ”This work presents the most convincing evidence to date of high temperature magnetism in the oxides.” Despite Moodera's recent advances, however, Wolf cautions that considerable obstacles remain before spin-based processors can become a commercial reality.
The most pressing problem is a phenomenon called ”spin scattering,” which Moodera concedes is ”one of our biggest challenges.” Due to physical properties of the metal he used to build his electron-injecting device, the electrons' spin often changes slightly from the time they are injected to the time they are read by the spin detector. Such changes compromise the accuracy of any information that might be transmitted using this technique.
Moodera's quest for a material that will not have this effect is ongoing. Awschalom and other researchers are experimenting with laser-based techniques designed to compensate for this erroneous rotation.
Another problem: the materials used to manufacture spin-based chips and circuits are prohibitively expensive. A 4-megabit magnetoresistive RAM (MRAM) chip, for instance, costs US $25, while nonmagnetic RAM chips with the same capacity typically cost only around $5. ”The only way the cost is going to come down is if the volume of production goes up, and that's a relatively slow process,” Wolf says.
Awschalom likens spintronics to laser research several decades ago—its key players, he says, are on the verge of a breakthrough with future repercussions they can scarcely predict themselves. ”Today's technology is so inarguably successful that it's hard to imagine spintronics could do better,” he says. ”But if you could make computer processors a million times faster, with a hundred million times more memory, then you could make enormous impacts on every field—from pharmaceutical design to weather prediction.”
I just hope by the time we surpass the 1 nanometer barrier, we won't be making "chips" based off silicon wafers. There are limits of fabrication processes near the 1-10 nm region because quantum mechanical effects like tunneling come into play when the wires are only a few atoms wide. If the wires are too close, electrons can tunnel between them. With such small wires, the whole current is carried by a few electrons. People are no doubt working on these and other related issues right now.
So perhaps by that time we will have moved on to optoelectronic, spintronic, or quantum components which require a non-traditional manufacturing process.
I guess the focus will be shifted to more difficult games like Go or Dark Chess (a game with incomplete information) which computers are still bad at.
> Not really ! The world is scheduled to end on December 21, 2012 ! :-)
I have heard of that, but be free, there is no such a thing :)
*Adds "Knowing" to his urgent must watch list*
And I´m sure, after there is no human life on earth, after there is no earth, before there is no intelligence in the world (universe): Chess isn´t solved!
This movie is very unrealistic. If something was threatening life in America, Obama would give a speech and the problem would be solved. Of course chess is much too trivial a problem for a guy who has received one and a half million dollars for fixing the world's economy, providing world peace, saving the planet from global warming, and providing all Americans with high quality, affordable health coverage.
You speak about million (10^6) dollars! I think, it´s trillion (10^12) dollars! The difference isn´t that small like many people think! :-)
Btw: You and Nelson tell us: Forward, Mr. Putin! Is Putin the last help for American Republicans? You need an (your old) enemy? What´s about: Forward, Mr. Hu Jintao (or Wen Jiabao)?
But the thinking is dangerous. With Reagan USA becomes an overwhelming armed state! Reagan hasn´t to show his strength, everybody was awed! After Reagan some think tanks thought, we have to make more profit with our overhelming army! And the pressure becomes greater and when there was a good reason (2001/09/11), Bush junior made it! Iraq!!?? This wasn´t wise! You know it from chess: a threat is better than to do it!
And Mr. Putin has to fight at his national borders! All border states of Russia are interested in NATO!? Are the NATO states interested in this states? Yes!! You see it in Georgia (and Ukraine)! Putin has a good legitimation to fight! And NATO states wash their hands!! Okay, some trouble, but maybe next time at an other place!
Where is the American President, who has to fight at his border? Cuba? Mexico? Canada?
I think we will have massive inflation and massive interest rates to go along with our massive taxes. If everyone makes over $250K, it will be OK for everyone to pay higher taxes, right? I am just waiting for the malaise speech...
> My only worry is that in 10 years chess will no longer be interesting at all. In 10 years from now Rybka's cluter combined with a much stronger version of Rybka will be powerful enough to solve chess (or almost completely solve it) so chess as an interesting game will end. It will simply be the end of chess.
If playing under fair conditions against Rybka, Chess 'as an interesting game' has gone for most of us.
We have interesting games against the machine, if she is handicapped. And this you can do in 10 and 50 years.
A machine will have solved chess within 10 years?
I cannot immagine, that this will come true. I doupt that they will have solved chess during the next 50 or 100 years!
And so engines-tests, engine-games and engine-rating-lists will exist in 10 and 20 years.
I will not have any reason to have less interests in that theme then than today!
Otherwise I should have deleted my engine-park many years ago. :-(
By the time chess is solved we will also have invented a way of warping empty space into ice cream cone shaped funnels for use as light scoops for star light; in other words, it's a long way off.
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