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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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New Material Sends Data Storage Into Overdrive
14 October 1998 7:00 pm
Japanese researchers have identified an oxide material that may soon greatly improve the storage capacity of hard disks and magnetic tapes. The discovery, reported in tomorrow's issue of Nature, relies on a phenomenon called colossal magnetoresistance--a large drop in a material's electrical resistance in response to an applied magnetic field--that has previously been seen only at very low temperatures.
Magnetoresistance is what allows the heads in a tape recorder or a disk drive to read data from the magnetic pattern on the tape or disk. It's the result of a particular magnetic property of materials--the magnetic moment, a tiny magnetic field produced by electrons orbiting the nucleus of an atom. In many crystalline materials, magnetic moments are randomly oriented, which increases the electrical resistance of the material. But a strong external magnetic field can reduce that resistance by bringing the magnetic moments into alignment. The larger the magnetoresistance of a material, the smaller the magnetic signal to which it can respond.
Until now, the largest resistance drops were seen only at very low temperatures; when using magnetoresistive materials in practical, everyday items, scientists had to settle for only a 1% or 2% reduction in resistance. But in crystals of an iron-molybdenum oxide, a team led by Kei-Ichiro Kobayashi at the Joint Research Center for Atom Technology in Tsukuba, Japan, saw a 10% drop in resistance when they placed the material in a strong magnetic field, considerably more than the one seen in comparable materials.
Because of the high magnetic field required to produce the magnetoresistance effect, Kobayashi says, the material isn't ready to be used in data storage devices. But scientists are heartened by the results. "[The change in resistance] is a huge effect," says Sang-Wook Cheong, a physicist at Rutgers University and Lucent Technologies' Bell Laboratories in New Jersey. The oxide's display of magnetoresistance at room temperature, he predicts, "will lead to more research on [similar] materials." And, Cheong adds, the possibility of turning this finding into improved disk storage and magnetic sensors "is very realistic."