Phys. Rev. B 60, 7385 (1999)
Crossover between ballistic and diffusive regime of spin-conductance and
CPP-GMR in magnetic multilayered nanostructures
S. Sanvito, C.J. Lambert, and J.H. Jefferson
We analyze the interplay between disorder and band structure
in current perpendicular to the planes giant magnetoresistance (GMR). We
consider finite magnetic multilayers attached to pure crystalline leads,
described by a tight-binding simple cubic two-band model (s-d
). Several models of disorder are considered, including random on-site potentials,
lattice distortions, impurities, vacancies, and cross-section fluctuations.
Magnetotransport properties are calculated in the zero-temperature zero-bias
limit, within the Landauer-Büttiker formalism. Using a very efficient
numerical scattering technique, we are able to perform simulations, over
large length scales, and to investigate spin transport in the ballistic,
diffusive, and localized regimes, as well as the crossover between them.
The competition between disorder-induced mean-free-path reduction and disorder-induced
spin asymmetry enhancement of the conductance highlights several different
regimes of GMR.