Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 15: Magnetic measurement methods
MA 15.8: Talk
Tuesday, March 17, 2015, 11:15–11:30, H 1012
A Ferromagnetic Resonance scanner with 20 µm resolution — •Carola Lottis, Ralf Meckenstock, Christian Schöppner, and Michael Farle — Faculty of Physics and CENIDE, University Duisburg-Essen, Germany
The enlarged surface-to-volume ratio of nano structures, inhomogeneous demagnetizing fields due to confined geometries, roughness and morphology have considerable influence on magnetic properties and lead to complex magnetic excitations. Here, we present a micro resonator technique used in combination with a submicrometer positioning system to determine magnetic properties of single nano magnets, that do not have to be prepared specially for- or in the micro resonator, but stay in their natural environment.
To reach a sensitivity of 106 spins for FMR detection, a micro resonator is evaporated on a silicon-nitrite membrane (250 µm x 250 µm and 200 nm thick). The FMR sensitive area is 20 µm and at a distance of <10 µm above the sample. An optical microscope is mounted above the FMR scanner to facilitate the positioning of the sample in the FMR sensitive area. The positioning system has a working range of 6.1 mm in all three directions with a resolution of 1 nm. First results on an iron silicon ferromagnetic stripe with a “zig-zag” form (65 µm long, 1.5 µm wide and 18 nm thick) will be shown. Small deviations of the FMR due to the zig-zag structure’s dipole field can be resolved.
The authors thank the DFG for financial support within the program LI1567/3-1.