Featured Research

from universities, journals, and other organizations

Ultra-high-density Data Storage May Become Practical With Breakthrough In Nanoscale Magnetic Sensors

Date:
February 3, 2003
Source:
National Science Foundation
Summary:
A simpler and more reliable manufacturing method has allowed two materials researchers to produce nanoscale magnetic sensors that could increase the storage capacity of hard disk drives by a factor of a thousand. Building on results reported last summer, the new sensors are up to 100 times more sensitive than any current alternative technology.

ARLINGTON, Va. -- A simpler and more reliable manufacturing method has allowed two materials researchers to produce nanoscale magnetic sensors that could increase the storage capacity of hard disk drives by a factor of a thousand. Building on results reported last summer, the new sensors are up to 100 times more sensitive than any current alternative technology.

Susan Hua and Harsh Deep Chopra, both professors at the State University of New York at Buffalo, report in the February issue of Physical Review B on their latest experiments with nanoscale sensors that produce, at room temperature, unusually large electrical resistance changes in the presence of small magnetic fields. The work is supported by the National Science Foundation (NSF), an independent federal agency that supports fundamental research and education across all fields of science and engineering.

“We first saw a large effect of over 3,000 percent resistance change in small magnetic fields last July,” Chopra said. “That was just the tip of the iceberg. These results point to the beautiful science that remains to be discovered.” The largest signal they have seen is 33 times larger than the effect they reported last summer, which corresponds to a 100,000 percent change in resistance.

As stored “bits” of data get smaller, their magnetic fields get weaker, which makes individual bits harder to detect and “read.” Packing more bits onto the surface of a computer disk, therefore, requires reliable sensors that are smaller, yet more sensitive to the bit’s magnetic field. Hua and Chopra’s nanoscale sensor seems to be ideally suited to the task.

For comparison, the technology in today’s hard disk drives relies on signals as weak as a 20 percent change in resistance. In other words, if sensor has a baseline signal of 1, an “off” bit causes Chopra and Hua’s sensors to spike at signal strength of –1,000, and an “on” bit registers +1,000. Current sensors, which only work on much larger bit sizes, would swing between an “off” signal of 0.8 and “on” of 1.2. The larger changes mean that the new sensors produce much more distinct and reliable signals than current technologies do, which would enable the bit size to be shrunk dramatically.

Chopra and Hua’s sensors have another advantage over other experimental techniques that are currently being studied: Because of the sensors’ high sensitivity at room temperature, they would be straightforward to adapt to work with existing technologies used by the $25 billion hard disk drive industry. Chopra predicts that their sensors would permit disk capacities on the order of terabits (trillions of bits) per square inch.

Their success builds on an effect called “ballistic magnetoresistance” (BMR). “Magnetoresistance” measures the change in electrical resistance when a device is placed in a magnetic field. Many types of magnetoresistance are being explored for sensors that might find use in hard disk drives. The magnetoresistance effect goes “ballistic” when an electron must cross a channel so narrow that the electron shoots straight through without scattering. In a normal wire, an electron zigzags its way through the material in a process called “diffusive” transport.

Chopra and Hua created their ballistic-effect sensors by forming nanoscale nickel “whiskers” between two larger nickel electrodes. Their current experiments include confirmation of the structure and composition of the whiskers with scanning electron microscopy.

The researchers suspect that the ballistic effect stems from pinch points, or constrictions, in the whiskers produced during manufacturing. The new manufacturing method, which also allowed them to reliably produce nanosensors with the desired effect, is therefore a key to Chopra and Hua’s latest success.

Chopra and Hua modified and adapted a method of producing controlled nanoscale wires originally developed b y Arizona State University’s Nongjian Tao, whose work is also supported by NSF. Tao’s electrodeposition method allowed Chopra and Hua to specify in advance the resistance they wanted from their nanoscale whiskers. They can now reproduce their contacts reliably and simply, as opposed to the hit-or-miss method they had used previously. “We have been consistently able to produce contacts with BMR effects of several thousand percent,” Chopra said.

Besides disk drives, these types of sensors may also have biomedical applications. For example, the sensor’s electrical properties might be used to detect biomolecules in solution, even in low concentrations, according to Chopra. By attaching itself to the sensor, each type of biomolecule would impart its own “fingerprint” by changing the electrical signal of the nanocontact.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "Ultra-high-density Data Storage May Become Practical With Breakthrough In Nanoscale Magnetic Sensors." ScienceDaily. ScienceDaily, 3 February 2003. <www.sciencedaily.com/releases/2003/02/030203075918.htm>.
National Science Foundation. (2003, February 3). Ultra-high-density Data Storage May Become Practical With Breakthrough In Nanoscale Magnetic Sensors. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2003/02/030203075918.htm
National Science Foundation. "Ultra-high-density Data Storage May Become Practical With Breakthrough In Nanoscale Magnetic Sensors." ScienceDaily. www.sciencedaily.com/releases/2003/02/030203075918.htm (accessed September 18, 2014).

Share This



More Matter & Energy News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

Newsy (Sep. 16, 2014) MIT developed a robot modeled after a cheetah. It can run up to speeds of 10 mph, though researchers estimate it will eventually reach 30 mph. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins