Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Magnetismus
MA 36: Magnetic Coupling Phenomena / Exchange-Bias
MA 36.3: Vortrag
Freitag, 31. März 2006, 11:15–11:30, HSZ 401
Dilution and grain size effect on ferromagnetic/antiferromagnetic exchange biased bilayers with low anisotropy — •Marian Fecioru-Morariu1, Cristian Papusoi2, Jan Hauch1, and Gernot Güntherodt1 — 1II. Physikalisches Institut, RWTH Aachen, Huyskensweg, 52074 Aachen, Germany — 2MINT Center, 205 Bevill Building, Box 870209, University of Alabama, Tuscaloosa, AL 35487, USA
The effect of inserting nonmagnetic substitutional defects (dilution) in antiferromagnets (AFMs) was tested in high anisotropy AFMs, such as CoO, in Co/CoO exchange biased bilayers [1]. We have extended this study to low anisotropy AFMs, such as FeMn, in which the effects of the substitutional, nonmagnetic Cu defects on the exchange bias (EB) are tested. In addition, by using different Cu buffer layer thicknesses, we are able to test the effect of different AFM grain sizes on the EB and blocking temperature. By using Cu-diluted NiFe/FeMn exchange biased bilayers we have observed a maximum of the exchange bias field as a function of the Cu dilution. At the same time the blocking temperature decreases. In order to clarify the reason for decreasing the blocking temperature we have measured the thermoremanent magnetization (TRM) of the AFM itself. By means of a time quantified Monte-Carlo simulation on the basis of a Heisenberg model, we are able to describe all the above experimental observations of the EB field, blocking temperature and coercive field.
1. J.Keller, P.Miltenyi, B.Beschoten, G.Guntherodt, U.Nowak and K.D.Usadel, Phys. Rev. B 66, 014431 (2002)