Regensburg 2004 – scientific programme

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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.52: Poster

Tuesday, March 9, 2004, 15:00–19:00, Bereich A

Kerr observations of asymmetric magnetization reversal in CoFe-IrMn bi-layer systems — •Jeffrey McCord¹ and Roland Mattheis² — ¹IFW Dresden, Helmholtzstr. 20, 01169 Dresden — ²IPHT Jena, Albert-Einstein-Str. 9, 07745 Jena

The magnetization reversal process in the ferromagnetic layer of exchange-biased CoFe-IrMn film structures, deposited by dc-magnetron sputtering, is imaged Kerr microscopy. The amount of magnetization rotation at different field directions is quantified by measuring the longitudinal and transversal magnetization components during reversal.

A strong asymmetry, both in domain behavior and magnetization loops, between the forward and recoil branch of the magnetization reversal is found. The magnitude of asymmetry strongly depends on small angle misalignments between the direction of exchange-bias and the external magnetic field. The observed behavior is explained by anisotropy dispersion in the ferro- and antiferromagnetic layer. Influencing the effective anisotropy distribution in the CoFe-IrMn system leads to differently pronounced asymmetries. The differences for both branches of the hysteresis loop are described in terms of domain nucleation mechanisms due to changes leading to an effectively wider anisotropy distribution.