11-02/03 :: February / March 2011

nanotimes News in Brief

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a diameter of 0.30 thousandth of a millimeter (300 nanometers) on top of a thin magnetic layer. Under specific conditions, all of these glass spheres arrange next to each other and therefore form a mask of tiny hexagons with small gaps. When the scientists direct argon ions at this layer, these atomic and electrically charged projectiles penetrate the gaps between the glass spheres and force particles out of the magnetic layer located under the gaps. The array of the glass spheres, thus, functions as a mask: One magnetic disk remains below each individual glass sphere, whi- le the magnetic layer under the gaps erodes. During the bombardment, though, the argon ions remove material from the glass spheres which, according to that, continuously decrease in size.

At the end of the process the diameter of the glass spheres is only 260 nanometers, instead of the ori- ginal 300 nanometers. This permits the argon ions to reach also areas which are located further inside the magnetic disks that are emerging beneath the glass spheres over time. Because the time of bom- bardment is shorter in these places, less material is removed on the inside. The desired slanted edge is therefore created virtually on its own.

Image on page 1: Slanted exterior edges allow tiniest magnetic vortices on nano disks, one disk having a diameter of 150nm. Each vortice is directed either upwards or downwards. Together with the direction of the magnetic rotation each magnetic disk can take four different states on the smallest space. © S. Münster, Kunstkosmos

Norbert Martin, Nadja-Carola Bigall, Ingolf Mönch, Tho- mas Gemming, Alexander Eychmüller, Roland Mattheis, Rudolf Schäfer, Ludwig Schultz, Jeffrey McCord: Enhanced Nucleation of Vortices in Soft Magnetic Materials Prepared by Silica Nanosphere Lithography, In: Advanced Functio- nal Materials, Volume 21(2011), Issue 5, March 8, 2011, Pages 891-896, DOI:10.1002/adfm.201002140: http://dx.doi.org/10.1002/adfm.201002140

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