Dresden 2011 – scientific programme
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MA: Fachverband Magnetismus
MA 62: Magnetic Imaging
MA 62.4: Talk
Friday, March 18, 2011, 11:30–11:45, HSZ 04
Contrast formation and deconvolution of pinned UCS by MFM — •Sevil Ozer1, Niraj Joshi1, Hans Josef Hug1,2, Miguel Marioni2, and Sara Romer2 — 1Department of Physics, University of Basel, CH-4056 Basel, Switzerland — 2EMPA, CH-8600 Dubendorf, Switzerland
In prior work we presented MFM images of pinned, uncompensated spins (UCS) at the antiferromagnet/ferromagnet (AF/F) interfaces in exchange-biased systems[1,2,3]. We argued that the MFM image obtained after saturation of the F arises from the pinned UCS. Here a detailed analysis of the different contributions to the measured MFM contrast is presented. To deconvolute the various contrast contributions, their behavior upon field reversal was studied. Our analysis reveals that the topography-induced variations of the vdW forces, the magnetic field mediated forces generated by variations in the F-layer thickness, roughness and saturation magnetization and those from the rotating UCS do NOT change sign upon field reversal. The contrast arising from the pinned UCS reverses, because the magnetization of the tip has flipped. After calibration of the imaging properties of the MFM tip by using the MFM data of F-domain image, the areal density of the pinned UCS can be devonvolved from the frequency shift MFM data of the pinned UCS.
[1] P. Kappenberger et al., Phys. Rev. Lett, 91 (2003) 267202
[2] I. Schmid et al., Europhys. Lett., 81 (2008) 17001
[3] I. Schmid et al., Phys. Rev. Lett., 105 (2010) 197201