Printer Friendly

Resistance leaps as magnetism mounts.

To makers of computer disk drives, the fainter the magnetic field a sensor can detect, the better. If data-reading heads can detect tinier data bits, which have weaker fields, manufacturers can cram more data into less disk space (SN: 4/3/99, p. 223).

Today, commercial read heads are made of layers of magnetic metals stacked into sandwich structures whose electrical resistance changes in response to a varying magnetic field. These so-called giant magnetoresistance heads change their resistance at room temperature by about 5 percent in the presence of a magnetic bit of data, says Stuart A. Solin of NEC Research Institute in Princeton, N.J.

In the Sept. 1 SCIENCE, he and his colleagues unveil a new type of magnetoresistive device about the size of a pinhead. More like a traffic rotary for electrons than a sandwich, it could raise commercially useful magnetoresistance to new heights.

In more recent, unpublished experiments, "we've already obtained over 2,000 percent [resistance change] at magnetic fields relevant to read heads," Solin told SCIENCE NEWS. At high magnetic fields, the researchers have measured resistance change of up to 1 million percent.

Solin and his colleagues have coined a new phrase to describe their invention's behavior: "extraordinary magnetoresistance." To make a device demonstrating the effect, the researchers first deposit a ring of indium-antimonide, about a micrometer thick, onto a gallium-arsenide plate. Then, they fill its center with gold.

In the absence of a magnetic field, current passes handily through the gold, so the resistance is tiny. However, a magnetic field exerts a perpendicular force on moving electrons. As the researchers raise the magnetic field, this deflection forces more current into the indium-antimonide, where resistance is high.
COPYRIGHT 2000 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2000, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:development of new type of magnetoresistive device
Author:P.W.
Publication:Science News
Article Type:Brief Article
Geographic Code:1USA
Date:Sep 16, 2000
Words:282
Previous Article:Robots making robots, with some help.
Next Article:Risky Business.
Topics:


Related Articles
Magnetic advantage; magnetic fields make new thin films better conductors.
New memories tap spin, gird for battle.
Abracadabra! Magnets float in midair.
20 YEARS Of Storage Milestones.
To Be Fully Informed[ldots].
Magnifier May Crack Crimes, Crashes.
Precessional switching in magnetic memory devices demonstrated by NIST. (News Briefs).
Sharper shaft points to smaller bits. (Heightened Resistance).
NIST uses high-frequency noise to characterize commercial recording heads.
MRAM runs six times faster than DRAM; can it supercharge your systems?

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |