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

Paper MI-TuP2
Iron-silicide Phases Formed in Fe/Si Multilayered Films

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

Session: Aspects of Magnetism
Presenter: J.S. Park, Hanyang University, Korea
Authors: J.S. Park, Hanyang University, Korea
Y.V. Kudryavtsev, Institute of Metal Physics, Ukraine
J. Dubowik, Institute of Molecular Physics, Korea
J.Y. Rhee, Hoseo University, Korea
Y.P. Lee, Hanyang University, Korea
Correspondent: Click to Email
Fe/Si multilayers films (MLF) can have the interfacial layers of various iron silicides and were recently discovered to have an antiferromagnetic (AF) coupling in the as-deposited state. An ion-beam mixing (IBM) allows us to overcome either thermodynamic or kinetic barriers by employing the energetic particles, to surpass the limit of solid solubility and to achieve the compositional and structural metastability. Fe/Si MLF with various sublayer thicknesses were made by RF sputtering onto glass substrates and an IBM was also performed. The structural properties before and after the IBM turned out to be very different. A study of the optical and magneto-optical (MO) properties of the as-deposited MLF reveal that neither FeSi@sub 2@ nor @epsilon@-FeSi could be considered as the spacer layer providing the strong AF coupling, but that a B2-phase nonmagnetic metallic FeSi compound is spontaneously formed between Fe sublayers during deposition. The IBM of the Fe/Si MLF has been performed at room temperature (RT) by using Ar@super +@ ions with an energy of 80 keV, a dose of 1x10@super 16@ ions/cm@super 2@ and a flux of 1.5x10@super -6@ A/cm@super 2@. The magnetic properties were measured at RT by vibrating-sample magnetometry and ferromagnetic-resonance spectroscopy. The ion-beam treatment has led to noticeable changes in the structural and physical properties of Fe/Si MLF : the formation of a new phase, which is characterized by a crystalline silicide structure, a low coercivity and a Curie temperature of about 550 K. The obtained results can be explained if a metastable FeSi@sub 2@ silicide with a B2-type structure is supposed.