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AM: Magnetismus

AM 17: Mikromagnetismus II (Dots, Partikel)

AM 17.10: Vortrag

Freitag, 30. März 2001, 12:30–12:45, S 5.4

Micromagnetic characterisation of exchange bias and structured thin layer systems using MXCD — •Uwe Muschiol¹, S. A. Nepijko¹, A. Oelsner², O. Schmidt², O. de Haas¹, G. Schönhense² und C. M. Schneider¹ — ¹IFW-Dresden, Helmholtzstr. 20, 01069 Dresden — ²Inst. of Physics, University Mainz, Staudingerweg 7, 55099 Mainz

The domain structure of magnetron dc-sputtered permalloy /NiO/ permalloy systems was investigated by magnetic circular dichroism (MXCD) using photo emissions electron microscopy (PEEM). Measurements were carried out at the 4.2 R beamline in Trieste (Italy) and at the ID UE56/1 at BESSY II (Berlin). We focus on two important items.   How influences a exchange bias system like Py(fm)/NiO(afm) shape, size, and number of magnetic domains for large (∼ 100 µ m) and medium (∼ 20 µ m) size structured elements. We observe domain pattern, which not correspond to a simple Landau-Lifshitz flux closure structure and show multi-domain state whenever the magnetisation vector is expected to point perpendicular to the incoming light. Thus the domain pattern reflects an uniaxial or an unidirectional anisotropy.   By varying structures size and shape we investigate how this influences the formation of magnetic domains. Scaling down these elements a sequence of different domain states occur beginning with closure domains, then a two-state is established, where the domains aligned opposite. In the end, only the one-domain state is realised. If only one dimension is decayed, a much more complex domain sequence is observed. In this case it is feasible to adjust an increased magnetic stiffness by choosing a certain a/b ratio.