College Park, Maryland June 6 - 10 , 2004
MP48: Magnetic structure of Cu(Mn)/Cu superlattices
W. Donner, L.B. Carvalho (Department of Physics, University of Houston), J.L. Robertson (Reactor Division, Oak Ridge National Laboratory)
Cu(Mn) alloys are the prototype for spin-glass behavior and at the same time exhibit spin-density waves of a limited (20 Å) correlation range. We are interested in short-range order in thin films in general and have chosen Cu(Mn) as a model system to study the effect of confinement on short-range order. In order to obtain a large enough number of scatterers for a neutron experiment we prepared superlattices of Cu(Mn)layers separated by Cu. The samples have been epitaxially grown by DC-magnetron sputtering onto Si(001) substrates with a Cu(001) buffer layer. They exhibit a mosaic of about 0.7 degrees and show very little structural disorder as evidenced by high-order structural satellite peaks in x-ray diffraction experiments.
We will present first results obtained at the High Flux Isotope Reactor in Oak Ridge (HB1A) on samples with varying Cu(20 at-% Mn) and Cu thickness. Both strongly modulated magnetic short-range order and magnetic long-range order are present in the samples when the Cu(Mn) thickness is below 20 Å.
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