Spin-dependent transport in films composed of Co clusters and C60 fullerenes
Institut, Universität zu Köln, Zülpicher Str. 77, 50937
Corresponding author: a email@example.com
Published online: 3 August 2004
Granular films of Co-cluster/C60 mixtures have been prepared by the co-deposition of well defined Co clusters (mean diameter ≈4.5 nm) and C60 fullerenes onto a cold (≈35 K) substrate. Films having a Co cluster volume fraction show a resistivity , typical for tunneling with a Coulomb barrier. The tunneling magnetoresistance (TMR) has a value of TMR (% for and is decreasing by almost one order of magnitude going to . We explain this unusual decrease of the TMR with increasing vCo as caused by electron-doping of the C60 fullerenes due to the known charge transfer process occurring between transition metal surface and C60. Increasing electron doping may lead to an increasing probability for spin-flip processes within the tunneling barrier, resulting in a decrease of the TMR.
PACS: 75.47.-m – Magnetotransport phenomena; materials for magnetotransport / 73.40.Gk – Tunneling / 73.40.Rw – Metal-insulator-metal structures
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004