AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Wednesday Sessions
       Session MI-WeA

Paper MI-WeA2
Exchange Bias in Fe/Cr Double Superlattices

Wednesday, October 27, 1999, 2:20 pm, Room 618/619

Session: Giant Magnetoresistance
Presenter: J.S. Jiang, Argonne National Laboratory
Authors: J.S. Jiang, Argonne National Laboratory
G.P. Felcher, Argonne National Laboratory
A. Inomata, Argonne National Laboratory
R. Goyette, Argonne National Laboratory
C. Nelson, Argonne National Laboratory
S.D. Bader, Argonne National Laboratory
Correspondent: Click to Email
The exchange bias effect is a magnetic pinning phenomenon at the interface between a ferromagnet (F) and an antiferromagnet (AF). It is characterized by a field-offset, or "biased", hysteresis loop. Research on the exchange bias effect has been limited by difficulties in identifying the interfacial magnetic structure and in assessing the role of interfacial roughness. The strength of exchange bias typically observed experimentally is more than an order of magnitude smaller than that predicted by theory. We demonstrate the exchange-bias effect in sputter-deposited epitaxial Fe/Cr "double superlattice" structures that consist of ferromagnetically and antiferromagnetically coupled Fe/Cr superlattices. The AF/F interface in our novel double superlattices is coherent compared to conventional exchange bias systems consisting of dissimilar AF and F phases. The double superlattices offer flexibility in configuration and tunablity of the magnetic coupling and anisotropy. Magnetization results show that AF/F exchange coupling affects the nucleation of reverse magnetic domains, and that the magnitude of the exchange bias field is given directly by the classic formula for collinear spin structures. The collinear spin distribution is confirmed by polarized neutron reflectivity. Work supported by US-DOE BES-MS Contract No. W-31-109-ENG-38.