Nanoscale edge variations observed with record-breaking resolution in magnetic nanodevices

Mar 28, 2013
Ferromagnetic resonance force microscopy image of the precession of an edge mode in a 500 nm diameter permalloy disk. The disk appears as a blue region, and the precession of the edge mode appears as a purple peak on the right.

(Phys.org) —A team of researchers from the Royal Institute of Technology, Stockholm, the University of Maryland, and the NIST Center for Nanoscale Science and Technology have measured large variations in the magnetic properties along the edge of a thin film 500 nm-diameter disk. This work represents a significant development in the measurement of magnetic thin film edge properties, which are especially important for nanodevices, such as magnetic memory cells, where the edge to area ratio is large.

The researchers' technique, called force microscopy, detects magnetic resonance in a sample through changes in the magnetic force between the sample and a magnetic cantilever tip. The technique uses an external field from a nearby microwave antenna to excite a magnetic resonance that causes the sample's magnetization to precess, wobbling like a top, billions of times per second. This precession leads to a small decrease in the time-averaged magnetization that can be detected as a change in the on the cantilever. With an external field applied in the plane of the film, modeling predicts that an "edge mode" forms in which the precession is localized to within 30 nm of the edge. The recent measurements profiled that edge mode with a record 100 nm resolution. By rotating the applied field direction, the location of the edge mode is then moved along the circumference of the disk, with changes in the mapping out variations in magnetic properties along the edge.

The researchers believe that continued development of ferromagnetic resonance force microscopy methods will enable measurements of individual magnetic nanodevices, providing important new information about the properties of these devices and their potential defects.

Explore further: Scanning tunnelling microscopy: Computer simulations sharpen insights into molecules

More information: Guo, F., Belova, L. and McMichael, R. Physical Review Letters 110, 017601 (2013). link.aps.org/doi/10.1103/PhysRevLett.110.017601

add to favorites email to friend print save as pdf

Related Stories

New method for imaging defects in magnetic nanodevices

Sep 13, 2012

(Phys.org)—A team of researchers from the NIST Center for Nanoscale Science and Technology, the Royal Institute of Technology, Stockholm, and the University of Maryland have demonstrated a microscopy method ...

Recommended for you

Protons fuel graphene prospects

Nov 26, 2014

Graphene, impermeable to all gases and liquids, can easily allow protons to pass through it, University of Manchester researchers have found.

Cooling with the coldest matter in the world

Nov 24, 2014

Physicists at the University of Basel have developed a new cooling technique for mechanical quantum systems. Using an ultracold atomic gas, the vibrations of a membrane were cooled down to less than 1 degree ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.