Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Magnetic Thin Films I
MA 15.7: Vortrag
Dienstag, 26. Februar 2008, 12:00–12:15, H 1012
Strain-modulated ferromagnetic resonance of Co thin films — •Andreas Brandlmaier1, Mathias Weiler1, Stephan Geprägs1, Matthias Opel1, Sebastian T. B. Goennenwein1, Rudolf Gross1, Christoph Bihler2, Hans Huebl2, and Martin S. Brandt2 — 1Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner-Str. 8, 85748 Garching — 2Walter Schottky Institut, Technische Universität München, 85748 Garching
Ferromagnetic resonance spectroscopy (FMR) is a powerful technique for the quantitative measurement of magnetic anisotropy in ferromagnetic materials. To improve sensitivity, most FMR setups are equipped with magnetic field modulation and lock-in detection. In this regard, an interesting alternative is the modulation of the ferromagnetic properties of the sample itself. This can be achieved by exploiting the magneto-elastic effect, via the application of a time-varying stress to the ferromagnetic sample.
We use piezoelectric actuators to generate a time-varying strain in Co or Ni thin films. The ferromagnetic films are evaporated directly onto the actuators to achieve perfect strain transmission. Using a X-band FMR spectrometer operating at 9.3 GHz, we have recorded the FMR of the films. We hereby used both conventional magnetic field modulation, as well as strain-modulation. We compare both detection techniques, and show that strain-modulated FMR allows to directly measure the magneto-elastic coefficients, given that the applied strain is quantitatively known.
This work is supported by the DFG via SPP 1157.