AVS 49th International Symposium
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI-TuP

Paper MI-TuP11
The Effect of the Ferromagnet/Antiferromagnet Interface on Magnetic Properties of Fe/KCoF@sub 3@ System

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Aspects of Magnetism
Presenter: Z. Celinski, University of Colorado at Colorado Springs
Authors: L.M. Malkinski, University of Colorado at Colorado Springs
T. O'Keevan, University of Colorado at Colorado Springs
R.E. Camley, University of Colorado at Colorado Springs
Z. Celinski, University of Colorado at Colorado Springs
D. Skrzypek, University of Silesia, Poland
Correspondent: Click to Email
The Molecular Beam Epitaxy (MBE) system was used to grow Fe/KCoF@sub 3@ bilayers, a ferromagnet-antiferromagnet system. Depending on deposition conditions the fluoride can be grown on the single crystal Fe layer in either single crystal or polycrystalline forms. Structural properties of our samples were carefully studied using X-rays, Reflection High Energy Electron Diffraction (RHEED) and tunneling electron microscopy. The structure of the fluoride determines the ferromagnet/antiferromagnet interface and significantly modifies magnetic properties, which were measured using Ferromagnetic Resonance (FMR) and SQUID magnetometry. We observed changes in the exchange bias which correspond to different structural states of the antiferromagnet. This could result in different spin compensations at the Fe/KCoF@sub 3@ interface in single crystal and polycrystalline samples. The interface also had a dramatic effect on the four-fold magnetocrystalline anisotropy of Fe. For the samples with polycrystalline KCoF@sub 3@ , the anisotropy thickness dependence for the single crystal Fe film, with thickness d ranging from 0.9 to 3 nm, showed a deviation from the usual 1/d dependence. The temperature dependence of the four-fold anisotropy of the samples with single crystal fluoride was typical of single crystal Fe films. However, the films with polycrystalline fluoride exhibited a distinctly different temperature behavior. The anisotropy for these samples increases significantly with decreasing temperature. The enhancement of the anisotropy was most pronounced for the samples with the thinnest Fe film changing by a factor of 3 from room temperature to low temperature. This effect is probably due to a specific morphology of the interface between the ferro- and antiferromagnet. In addition, a large rotational magnetic anisotropy, associated with the interaction between Fe and KCoF@sub 3@ , was evaluated from the temperature dependence of the FMR fields.