Navigation Links
Physicists measure current-induced torque in nonvolatile magnetic memory devices
Date:3/9/2011

ITHACA, N.Y. - Tomorrow's nonvolatile memory devices computer memory that can retain stored information even when not powered will profoundly change electronics, and Cornell University researchers have discovered a new way of measuring and optimizing their performance.

Using a very fast oscilloscope, researchers led by Dan Ralph, the Horace White Professor of Physics, and Robert Buhrman, the J.E. Sweet Professor of Applied and Engineering Physics, have figured out how to quantify the strength of current-induced torques used to write information in memory devices called magnetic tunnel junctions. The results were published online Feb. 28 in the journal Nature Physics.

Magnetic tunnel junctions are memory storage devices made of a sandwich of two ferromagnets with a nanometers-thick oxide insulator in between. The electrical resistance of the device is different for parallel and nonparallel orientations of the magnetic electrodes, so that these two states create a nonvolatile memory element that doesn't require electricity for storing information. An example of nonvolatile memory today is flash memory, but that is a silicon-based technology subject to wearing out after repeated writing cycles, unlike magnetic memory.

What has held back magnetic memory technology is that it has required magnetic fields to switch the magnetic states that is, to write information. This limits their size and efficiency because magnetic fields are long-ranged and relatively weak, so that large currents and thick wires are needed to generate a large-enough field to switch the device.

The Cornell researchers are studying a new generation of magnetic devices that can write information without using magnetic fields. Instead, they use a mechanism called "spin torque," which arises from the idea that electrons have a fundamental spin (like a spinning top). When the electrons interact with the magnets in the tunnel junctions, they transfer some of their angular momentum. This can provide a very strong torque per unit current, and has been demonstrated to be at least 500 times more efficient than using magnetic fields to write magnetic information, Ralph said.

To measure these spin torques, the researchers used an oscilloscope in a shared facility operated by Cornell's Center for Nanoscale Systems. They applied torque to the magnetic tunnel junctions using an alternating current and measured the amplitude of resistance oscillations that resulted. Since the resistance depends on the relative orientation of the two magnets in the tunnel junction, the size of the resistance oscillations could be related directly to the amplitude of the magnetic motion, and hence to the size of the torque.

The researchers hope such experiments will help industry make better nonvolatile memory devices by understanding exactly how to structure them, and also, what materials would best be used as the oxide insulators and the ferromagnets surrounding them.


'/>"/>

Contact: Blaine Friedlander
bpf2@cornell.edu
607-254-8093
Cornell University
Source:Eurekalert

Related biology technology :

1. McGill physicists find a new state of matter in a transistor
2. U of T physicists squeeze light to quantum limit
3. Physicists discover important step for making light crystals
4. Nanophysicists find unexpected magnetic effect
5. NYU physicists find way to explore microscopic systems through holographic video
6. Physicists at UC Santa Barbara make discovery in quantum mechanics
7. U-M physicists create first atomic-scale map of quantum dots
8. Physicists capture first images of atomic spin
9. UBC, Max Planck formalize partnership among worlds top quantum physicists
10. UC Riverside physicists pave the way for graphene-based spin computer
11. Rice physicists discover ultrasensitive microwave detector
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/23/2016)... ... May 23, 2016 , ... The need for blood donations in South Texas and across the ... Texas Blood & Tissue Center, blood donations are on the decline. In fact, donations across ... down 21 percent in South Texas in the last four years alone. , There is ...
(Date:5/23/2016)... , May 23, 2016 Zimmer Biomet Holdings, Inc. ... today announced that its Board of Directors has approved the ... second quarter of 2016. The cash dividend ... July 29, 2016 to stockholders of record as of the ... dividends are subject to approval of the Board of Directors ...
(Date:5/23/2016)... and LONDON , May 23, 2016 ... Frontage Boost Efficiency by 40% - Frontage Implement a ... Frontage Enforce Quality, Compliance and Traceability Within the Bioanalytical lab ... in the United States and ... be deployed across its laboratory facilities. In addition to serving as ...
(Date:5/23/2016)... ... May 23, 2016 , ... Foresight ... nanotechnology, announced the winners for the 2015 Foresight Institute Feynman Prizes. , ... in two categories, one for experiment and the other for theory in nanotechnology. ...
Breaking Biology Technology:
(Date:3/17/2016)... , March 17, 2016 ABI Research, ... forecasts the global biometrics market will reach more ... 118% increase from 2015. Consumer electronics, particularly smartphones, ... fingerprint sensors anticipated to reach two billion shipments ... Dimitrios Pavlakis , Research Analyst at ABI ...
(Date:3/14/2016)... 14, 2016 http://www.apimages.com ) ... --> - Renvoi : image disponible via AP ... --> --> DERMALOG, le leader ... nouveaux lecteurs d,empreintes digitales pour l,enregistrement des réfugiés ... utilisé pour produire des cartes d,identité aux réfugiés. ...
(Date:3/10/2016)... BELL, Pa. , March 10, 2016   Unisys ... U.S. Customs and Border Protection (CBP) is testing its ... San Diego to help identify certain ... States . The test, designed to help determine the ... pedestrian environment, began in February and will run until May ...
Breaking Biology News(10 mins):