Particle size dependence of the giant magnetoresistance in granular Ag‐Co0.4Ni0.6grown epitaxially on MgO{100}
| Autor: | D. J. Kubinski, H. Holloway, J. Hangas |
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| Rok vydání: | 1995 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 77:3331-3337 |
| ISSN: | 1089-7550 0021-8979 |
| Popis: | 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≳100 A 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... |
| Databáze: | OpenAIRE |
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