Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 15: Magnetische Kopplungsph
änomene / Exchange Bias
MA 15.1: Vortrag
Samstag, 5. März 2005, 14:00–14:15, TU H1028
Dilution dependence of the irreversible domain state magnetization in antiferromagnetic Co1−yO (100) and its relevance for exchange bias in Co/Co1−yO — •Reza Ghadimi, Bernd Beschoten und Gernot Güntherodt — 2. Physikalisches Institut, RWTH Aachen, Templergraben 55, 52056 Aachen
In the domain state model (DSM), exchange bias in ferro-/antiferromagnetic (FM/AFM) bilayers is attributed to the formation of a domain state in the volume of the antiferromagnet, which develops during field cooling. The domain state carries an irreversible domain state magnetization MIDS which yields uncompensated spins at the FM/AFM interface triggering and controlling the exchange bias [1-3]. Here, we use epitaxial Co1−yO(100) layers which grow untwinned on MgO(100)-substrates. The non-magnetic defects are intentionally introduced by overoxidizing CoO leading to Co deficiencies in Co1−yO. The irreversible domain state magnetization is measured after field cooling in B = 7T using SQUID magnetometry. Both, the dilution and temperature dependence of MIDS can directly by linked to the exchange bias field of corresponding samples with an additional ferromagnetic Co layer. Supported by DFG/SPP1133
[1]P. Miltényi, et al. Phys. Rev. Lett. 84, 4224 (2000) [2] J. Keller, et al. Phys. Rev. B 66, 014431 (2002) [3] U. Nowak, et al. Phys. Rev. B 66, 014430 (2002)