Magnetics Business & Technology - Spring 2013 - (Page 11)

RESEARCH & DEVELOPMENT Chaotic ‘Spin Vortices’ Could Lead to New Computer Memories Scientists at the US Department of Energy’s Argonne National discovered that the new polarizations corresponded to the oppoLaboratory have used alternating magnetic fields to control the site state of the applied frequency. If the frequency corresponded behavior of “spin vortices” trapped in small dots made from iron to the parallel magnetization, an antiparallel arrangement would and nickel that can be magnetized in two separate ways. While emerge, and vice versa. the majority of these structures are magnetized in-plane either “We were somewhat surprised that the behaviors of multiple clockwise or counter-clockwise, a tiny region at their centers, the dots could be controlled so precisely,” Jain said. “There had been vortex core, is magnetized out of plane, either up or down. a lot of work done before on single-dot systems, but no one had “If you were able to visualize it, it would look like a funnel,” really investigated how magnetic dots interact with each other in said Argonne materials scientist Valentyn Novosad. this kind of environment.” Novosad and postdoctoral researcher Shikha Jain wanted to find a way to control the magnetic states of pairs or even large groups of these dots that interacted with each other in a lattice. In the resting state, the cores of the dots are randomly polarized. After applying an oscillating magnetic field to the pairs of dots, the researchers observed that the central cores began to switch back and forth repeatedly between up and downTOTAL MAGNETIC SOLUTIONS magnetizations, which Jain and Novosad characterized as “chaos.” This chaotic system’s behavior is dictated by Across any application, Magnet Applications the fact that the magnetic field, when applied, os™ is able to provide the magnetic technology cillates at a particular frequency that can be tuned to match the “resonance frequency”. That is, the solution you are seeking. natural frequency of vibration, for a specific polarity combination in a dot-pair. Each pair of dots At Magnet Applications™ we have 50+ years as an OEM Supplier has two resonance frequencies, corresponding of Magnets. Our years of experience in the manufacture and design to parallel (up-up or down-down) or antiparallel of magnets and magnetic assemblies help you solve today’s tough (up-down or down-up) magnetization states. In design problems. the parallel state, the dot’s centers are magnetized in the same direction, while in the antiparallel With complete design capabilites and flexible manufacturing state they are opposite. methods, Magnet Applications™ is the ideal supplier. From By increasing and then decreasing the strength selecting the right material, to developing the best manufacturing of the applied field, Argonne’s scientists were able method, to delivery, to bring the dots’ magnetizations into and then out of chaos. When the amplitude of the oscillating field was reduced significantly, the researchers Visit for all your OEM magnet needs. MAGNET APPLICATIONS In this artist rendering, tiny magnetic vortices form on nanodisks, with each disk having a diameter of about 100 nanometers. Each vortex is directed either upwards or downwards. The Argonne study looked at the interaction between pairs of these nanodisks. Image courtesy Sander Munster, Dresden University of Technology (800) 437-8890 E-mail: ©2013 Bunting Magnetics Co. ® Spring 2013 • Magnetics Business & Technology 11

Table of Contents for the Digital Edition of Magnetics Business & Technology - Spring 2013

Magnetics Business & Technology - Spring 2013
Editor's Choice
Dysprosium-Free Rare Earth Magnets for High Temperature Applications
Research & Development
Simulating the Toyota Prius Electric Motor
Magnets • Materials • Measurement
Application • Component Developments
Industry News
Marketplace/Advertising Index
Spontaneous Thoughts: Dysprosium 2.0

Magnetics Business & Technology - Spring 2013