Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks

The electron spins in a magnetic vortex all point in parallel, either clockwise or counterclockwise. Spins in the crowded core of the vortex must point out of the plane, either up or down. The four orientations of circularity and polarity could form the cells of multibit magnetic storage and processing systems.
The electron spins in a magnetic vortex all point in parallel, either clockwise or counterclockwise. Spins in the crowded core of the vortex must point out of the plane, either up or down. The four orientations of circularity and polarity could form the cells of multibit magnetic storage and processing systems.

Abstract:
"We spent 15 percent of home energy on gadgets in 2009, and we're buying more gadgets all the time," says Peter Fischer of the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). Fischer lets you know right away that while it's scientific curiosity that inspires his research at the Lab's Advanced Light Source (ALS), he intends it to help solve pressing problems.

Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks

Berkeley, CA | Posted on May 22nd, 2013

"What we're working on now could make these gadgets perform hundreds of times better and also be a hundred times more energy efficient," says Fischer, a staff scientist in the Materials Sciences Division. As a principal investigator at the Center for X-Ray Optics, he leads ALS beamline 6.1.2, where he specializes in studies of magnetism.

Fischer recently provided critical support to a team led by Vojtĕch Uhlíř of the Brno University of Technology in the Czech Republic and the Center for Magnetic Recording Research at the University of California, San Diego. Researchers from both institutions and from Berkeley Lab used the unique capabilities of beamline 6.1.2 to advance a new concept in magnetic memory.

"Magnetic memory is at the heart of most electronic devices," says Fischer, "and from the scientist's point of view, magnetism is about controlling electron spin."

Magnetic memories store bits of information in discrete units whose electron spins all line up in parallel, pointing one way or the opposite to signify a one or a zero. What Fischer and his colleagues propose is multibit storage in which each unit has four states instead of two and can store twice the information.

The key is magnetic vortices - whirlpools of magnetic field - confined to tiny metal disks a few billionths of a meter (nanometers) in diameter. The electron spins are seeking the lowest possible energy; spins that point in opposing directions, antiparallel, cost energy. Thus the electrons line up with all their spins pointing in a circle, either clockwise or counterclockwise around the disk.

In the core of the vortex, however, where the circles get smaller and smaller and neighboring spins would inevitably align antiparallel, they tend to tilt out of the plane, pointing either up or down.

"So each disk has four bits instead of two - left or right circularity and up or down polarity of the core - but you must be able to control the orientation of each independently," says Fischer.

Up, down, and around - taking control

Applying a strong, steady external magnetic field can reverse core polarity, but practical devices can't tolerate strong fields, and they need faster switches. Previous researchers at the ALS had found that with weak oscillating magnetic fields in the plane of the nanodisk they could quickly nudge the core out of its central position and get the same result.

"Instead of a static field, you wiggle it," Fischer explains. As the core is pushed away from the center of the disk, successive magnetic waves - changes in spin orientation - move the core faster and faster until its polarity flips to the opposite orientation.

The team used ALS beamline 6.1.2 to demonstrate, for the first time, that similar methods can control the circularity of the magnetic vortices.

In this case, the "wiggle" drives the core right off the edge of the disk. Once it's expelled, the vortex collapses and reforms, with spins pointing in the opposite direction: clockwise instead of counterclockwise, or vice versa.

Beamline 6.1.2 specializes in soft x-ray transmission microscopy of magnetic states, which allowed the researchers to make direct images of how the strength and duration of the trains of electric and magnetic pulses affected the circularity of the vortex. They found that control depends on the disk's geometry.

The disks were all tapered, with diagonal slices off their top surfaces that served to accelerate the core, once it started moving. But thickness and diameter were the important factors: the smaller the disk, the better.

"Thick" disks (30 nanometers) over a thousand nanometers in diameter were sluggards, taking more than three nanoseconds to switch circularity. But disks only 20 nanometers thick and 100 nanometers across could switch orientation in less than half a nanosecond.

Much remains to be done before the four-value multibit becomes practical, Polarity can be controlled, and circularity can be controlled, but so far they can't be controlled at the same time. Plans for doing this are in the works.

"This is the scientific basis for possible applications to come," says Fischer. "We are already looking at ways to control spin with temperature and voltage, at how to completely decouple spin from charge currents, and even at ways to couple chains of nanodisks together to build logic devices - not just for memory, but for computation."

In Fischer's opinion, the ALS's soft x-ray microscopes tools are in the pole position for the race in magnetism research. "No method besides x-ray microscopy can provide similarly comprehensive information, both to identify the magnetic materials and to image the fastest dynamics of magnetic states on the nanoscale. The instruments we have are unique and serve the whole vortex community, world-wide."

DOE's Office of Science supports the ALS and, with the European Regional Development Fund and the Grant Agency of the Czech Republic, supported this research.

####

About DOE/Lawrence Berkeley National Laboratory
Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

The Advanced Light Source is a third-generation synchrotron light source producing light in the x-ray region of the spectrum that is a billion times brighter than the sun. A DOE national user facility, the ALS attracts scientists from around the world and supports its users in doing outstanding science in a safe environment. For more information visit www-als.lbl.gov/.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website at science.energy.gov.

For more information, please click here

Contacts:
Paul Preuss

510-486-6249

Copyright © DOE/Lawrence Berkeley National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

“Dynamic switching of the spin circulation in tapered magnetic nanodisks,” by Vojtĕch Uhlíř, Michal Urbánek, Lukáš Hladík, Jiří Spousta, Mi-Young Im, Peter Fischer, Nasim Eibagi, Jimmy Kan, Eric E. Fullerton, and Tomáš Šikola, appears in advance online publication of Nature Nanotechnology at:

For more about Fischer’s research on magnetic vortices, visit:

Visit for more about the Center for X-Ray Optics:

Related News Press

Imaging

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

News and information

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Laboratories

NREL’s Advanced Atomic Layer Deposition Enables Lithium-Ion Battery Technology: May 10th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

Sandia develops math techniques to improve computational efficiency in quantum chemistry May 5th, 2017

Scientists Set Record Resolution for Drawing at the One-Nanometer Length Scale: An electron microscope-based lithography system for patterning materials at sizes as small as a single nanometer could be used to create and study materials with new properties May 1st, 2017

Govt.-Legislation/Regulation/Funding/Policy

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Unveiling the quantum necklace: Researchers simulate quantum necklace-like structures in superfluids May 26th, 2017

Spintronics

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

First experimental proof of a 70 year old physics theory: First observation of magnetic phase transition in 2-D materials, as predicted by the Nobel winner Onsager in 1943 January 6th, 2017

Investigations of the skyrmion Hall effect reveal surprising results: One step further towards the application of skyrmions in spintronic devices December 28th, 2016

Electron highway inside crystal December 12th, 2016

Chip Technology

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Researchers find new way to control light with electric fields May 25th, 2017

Nanometrics Announces Retirement Plans of CEO Timothy Stultz: Dr. Stultz to Continue as Director May 25th, 2017

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Memory Technology

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

New ultrafast flexible and transparent memory devices could herald new era of electronics April 1st, 2017

Information storage with a nanoscale twist: Discovery of a novel rotational force inside magnetic vortices makes it easier to design ultrahigh capacity disk drives March 28th, 2017

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

Discoveries

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Announcements

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Controlling 3-D behavior of biological cells using laser holographic techniques May 26th, 2017

Tools

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

New metamaterial-enhanced MRI technique tested on humans May 26th, 2017

Nanometrics Announces Retirement Plans of CEO Timothy Stultz: Dr. Stultz to Continue as Director May 25th, 2017

Nanomechanics, Inc. to Exhibit at the SEM Conference: Nanoindentation experts will attend and exhibit their instruments at the Conference and Exposition on Experimental and Applied Mechanics in Indianapolis May 25th, 2017

Research partnerships

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

Ag/ZnO-Nanorods Schottky diodes based UV-PDs are fabricated and tested May 26th, 2017

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project