Eur. Phys. J. B 45, 137-146 (2005)
https://doi.org/10.1140/epjb/e2005-00172-9

A study of the induced magnetism in the Au spacer layer of Co/Au/CoO exchange-bias trilayers and related systems

¹ Hahn-Meitner Institut Berlin, 14109 Berlin, Glienicker Strasse 100, Germany
² Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin-Dahlem, Germany
³ Humboldt-Universität zu Berlin, Institut für Physik, 12489 Berlin, Germany
⁴ UCSF, San Francisco CA, USA

Corresponding author: ^a prandoli@physik.fu-berlin.de

Received: 17 November 2004
Published online: 16 June 2005

Abstract

We report the first observation of the effects of exchange bias on the nuclear spin polarization and induced magnetic moments at a magnetic/non-magnetic interface, applying low temperature nuclear orientation (LTNO) to Co/Au(x)/CoO trilayer systems. This technique allows us to determine simultaneously the average alignment of the nuclear moments for the two radioactive probe isotopes ¹⁹⁸Au and ⁶⁰Co with respect to an external magnetic field axis. The total average Au γ-ray anisotropy measured was found (i) to decrease with increasing Au thickness, indicating that large hyperfine fields are restricted to the interfacial Au layers and (ii) to be canted away from the applied field axis even when the Co layers are magnetically saturated. This canting was found to originate at the CoO/Au interface as could be shown from comparative measurements on CoO/Au/CoO trilayers containing two AFM CoO/Au interfaces and on a Co/Au/Co trilayer with two FM Co/Au interfaces. In the case of CoO/Au/CoO, the observed canting was found to be dependent on the Au layer thickness.