They now have a new tool developed by a team from the National Institute of Standards and Technology (NIST), the University of Maryland Nanocenter and the Royal Institute of Technology in Sweden — a method to detect defects in magnetic structures as small as a tenth of a micrometer even if the region in question is buried inside a multilayer electronic device.*
Trapped beneath the magnetic tip of a microscale cantilever, spin waves can be used to non-destructively measure the properties of magnetic materials and search for nanoscale defects, especially in multilayer magnetic systems like a typical hard drive, where defects could be buried beneath the surface. Credit: McMichael/NIST
The technique demonstrated at the NIST Center for Nanoscale Technology (CNST) builds on work by researchers at the Ohio State University.** The idea is to trap and image oscillating perturbations of a magnetic field—"spin waves"—in a thin film. Trapped spin waves provide scientists with a powerful new tool to nondestructively measure the properties of magnetic materials and search for nanoscale defects that could or have caused memory failures, especially in multilayer magnetic systems like a typical hard drive, where defects could be buried beneath the surface.
According to NIST researcher Robert McMichael, when left alone, the material's magnetization is like the surface of a pond on a windless day. The pond is comprised of smaller magnetic moments that come with the quantum mechanical "spin" of electrons. Tap the surface of the pond with a piece of driftwood, or microwaves in this case, and the surface will begin to ripple with spin waves as the microwave energy jostles the spins, which, in turn, jostle their neighbors.
"The trick we play is to tune the microwaves to a frequency just outside the band where the spin waves can propagate—except right under our magnetic probe tip," says McMichael. "It's like the pond is frozen except for a little melted spot that we can move around to check magnetic properties at different spots in the sample."
The trapped spin waves are disturbed by defects in the material, and this effect allows the defects to be characterized on 100 nm length scales.
Previous work had shown this same effect in magnetic spins that were oriented perpendicular to the magnetic film surface, meaning that the individual spins coupled strongly with their neighbors, which limited the resolution. This new work adds the extra feature that the magnetic spins are aligned in plane with one another and are not as tightly coupled. This setup is not only more representative of how many magnetic devices would be structured, but also allows for tighter focusing and better resolution.
* H-J. Chia, F. Guo, L.M. Belova and R. D. McMichael. Nanoscale spin wave localization using ferromagnetic resonance force microscopy. Physical Review Letters. 108, 087206 (2012). http://prl.aps.org/pdf/PRL/v108/i8/e087206.
** See Lee et al. Nanoscale scanning probe ferromagnetic resonance imaging using localized modes. Nature. 466, 12. Aug. 12, 2010. doi:10.1038/nature09279.
Mark Esser | EurekAlert!
Introducing the disposable laser
04.05.2016 | American Institute of Physics
New fabrication and thermo-optical tuning of whispering gallery microlasers
04.05.2016 | Okinawa Institute of Science and Technology (OIST) Graduate University
Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.
Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly...
If a person pushes a broken-down car alone, there is a certain effect. If another person helps, the result is the sum of their efforts. If two micro-particles are pushing another microparticle, however, the resulting effect may not necessarily be the sum their efforts. A recent study published in Nature Communications, measured this odd effect that scientists call “many body.”
In the microscopic world, where the modern miniaturized machines at the new frontiers of technology operate, as long as we are in the presence of two...
Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.
Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...
Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.
In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...
Honeycomb structures as the basic building block for industrial applications presented using holo pyramid
Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...
27.04.2016 | Event News
15.04.2016 | Event News
12.04.2016 | Event News
06.05.2016 | Earth Sciences
06.05.2016 | Life Sciences
06.05.2016 | Life Sciences