AVS 50th International Symposium
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+NS-TuA

Paper MI+NS-TuA10
Magnetic Reversal of Co/Pd Multilayer Films and Sub-100nm Islands

Tuesday, November 4, 2003, 5:00 pm, Room 316

Session: Self Assembly and Nanomagnetism
Presenter: G. Hu, Hitachi San Jose Research Center
Authors: G. Hu, Hitachi San Jose Research Center
T. Thomson, Hitachi San Jose Research Center
M.E. Best, Hitachi San Jose Research Center
B.D. Terris, Hitachi San Jose Research Center
C.T. Rettner, IBM Almaden Research Center
S. Raoux, IBM Almaden Research Center
G.M. McClelland, IBM Almaden Research Center
M.W. Hart, IBM Almaden Research Center
Correspondent: Click to Email
Patterned arrays of Co/Pd multilayer islands with perpendicular anisotropy are one approach to increasing magnetic recording density towards 1Tbit/in@super 2@. To realize this technology arrays consisting of single domain islands with sufficient anisotropy for thermal stability and a narrow switching field distribution will be required. In order to understand the reversal properties of islands we have compared the reversal mechanism and anisotropy of patterned arrays to nominally identical unpatterned, continuous films. The island arrays were fabricated by creating an etch mask using electron beam lithography and nano-imprinting followed by etching of a SiO@sub 2@ substrate. Multilayer films of Co/Pd were then sputter deposited onto the topographically patterned substrates. We found that for the continuous films, the magnetic anisotropy is only sensitive to the Co and Pd layer thicknesses while coercivity and magnetization reversal mechanism can be easily tuned by varying the deposition conditions. However, for small, single domain islands, the coercivity is much less sensitive to deposition conditions and more sensitive to composition than for the continuous films. The coercivity of these islands is generally significantly greater than that of the continuous films. Moreover, the switching behavior of the islands does not exhibit any correlation with the film reversal mechanism, but rather follows the film magnetic anisotropy closely. Systematic studies have been carried out to adjust the magnetic anisotropy of the multilayer films by varying the cobalt and palladium layer thicknesses. Unlike the continuous films, the measured coercivity of the islands agrees well with the reversal field calculated based on the measured anisotropy of the film and the Sharrock equation.