ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Measurements of structure and magnetoresistance in Ag-Co0.4Ni0.6 granular alloy films with 10–23.5 vol % Co0.4Ni0.6 grown epitaxially on MgO{100} are reported. These results elucidate the effects of varying both the concentration and the size of the Co0.4Ni0.6 precipitates in the Ag matrix. It is shown that the magnetic-field-dependent contribution to the resistivity, Δρmag, is consistent with the predictions of a two-current model in which spin-dependent scattering is dominated by the interfaces between the precipitates and the matrix. Specifically we observe: (a) A regime where Δρmag is linear in c/D, with c the volume fraction of precipitates with diameter D. (b) Extrapolation of these linear dependences to Δρmag=0 gives values of 1/D that are proportional to 1/c. (c) With D(approximately-greater-than)100 A(ring) there is a reduced dependence on particle size that is consistent with transition to a quadratic dependence. In contrast, at the lower concentrations the behavior of the maximum resistivity, ρmax, is not well described by the two-current model that suffices for Δρmag. This suggests that refinement of the model may be needed for granular films that have relatively large and widely spaced ferromagnetic precipitates. © 1995 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.359563
