AVS 49th International Symposium
    Magnetic Interfaces and Nanostructures Wednesday Sessions
       Session MI-WeA

Paper MI-WeA2
Mechanical Detection of Ferromagnetic Resonance in Micron-size YIG Disk

Wednesday, November 6, 2002, 2:20 pm, Room C-205

Session: Magnetization Dynamics
Presenter: V. Charbois, C.E.A. Saclay, France
Authors: V. Charbois, C.E.A. Saclay, France
O. Klein, C.E.A. Saclay, France
V.V. Naletov, Kazan State University, Russia
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We present room temperature measurements by Magnetic Resonance Force Microscopy (MRFM) of the ferromagnetic resonance (FMR) spectra on a normally magnetized YIG disk (with thickness 4.75µm and radius 80µm). The analysis of the influence of the tip for different probe-sample separation h led us to distinguish two cases. In the weak coupling regime, when the bias field generated by the tip is smaller than a few hundred Gauss, the prominent change is a shift of the entire spectrum to lower applied fields as h decreased. The result can be quantitativelly understood within the framework of the Damon and Eshbach model. In the strong coupling regime, the additional inhomogenous field produced by the tip can be used to localize new magnetostatic modes underneath the probe@footnote 2@ (this allows local spectroscopy to be performed). However, in the case of YIG, the spatial extension of these modes is limited to 4µm. Simultaneous measurements of FMR both by standard susceptibility and mechanical detection demonstrate the higher sensitivity of MRFM@footnote 1@ and its ability to measure smaller sample (in this case the spectroscopic response of the entire sample is obtained). Imaging of the magnetostatic modes can be performed by taking advantage of the localized probe. Ideally one should work at small h (to achieve high spatial resolution) with a tip producing a weak stray field (e.g. a tip coated with a thin film of ferromagnetic material). The last advantage of this technique is that it is sensitive to the longitudinal magnetization and thus it provides information complementary to conventional microwave susceptibility measurements. @FootnoteText@ @footnote 1@ V.Charbois, V.V.Naletov, J.Ben Youssef and O.Klein, J.Appl.Phys 91, 7337 (2002).@footnote 2@ V.Charbois, V.V.Naletov, J.Ben Youssef and O.Klein, to be published in Appl.Phys.Lett. (June 24@super th@ issue)