Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)

MA 15.81: Poster

Tuesday, March 27, 2007, 15:00–19:00, Poster A

Manipulating the dipolar magnetic interactions in FePt square arrays: The role of edge roughness — •Jonas Norpoth¹, Sebastian Dreyer¹, Christian Jooss¹, and Sibylle Sievers² — ¹Institut für Materialphysik, Friedrich-Hund-Platz 1, 37077 Göttingen — ²Physikalisch-Technische Bundesanstalt,Bundesallee 100, 38116 Braunschweig

The high magnetocrystalline anisotropy energy in hard magnetic materials may sustain magnetization distributions in the remanent state which exhibit a high number of magnetic surface charges and thus significant magnetic stray fields . Here, we focus onto the stray field distribution in the exterior and the demagnetization field distribution in the interior of hard magnetic FePt elements without and with artificial saw tooth edge roughness. The square elements are patterned by a focused ion beam. Magnetic stray field distributions are quantitatively measured by magnetic force microscopy (MFM) and a magneto-optic indicator film technique (MOIF). The demagnetization field distribution is calculated by magnetostatic methods. Our experiments and calculations reveal that external stray fields and internal demagnetization fields are considerably modified by the artificial edge roughness. Although the remagnetization process is dominated by nucleation of reverse domains at microstructural inhomogeneities, the inhomogeneous demagnetization field at rough sample edges significantly affects the remagnetization behaviour via the domain wall propagation.