Spin-dependent interface transmission and reflection in magnetic multilayers (invited)

Abstract

First-principles calculations of transmission and reflection from Ag/Fe, Au/Fe, Cu/Co, and Cu/Ni interfaces show very strong spin dependence that differs significantly from expectations based on free electron approximations. The results can be used to understand both the giant magnetoresistance and the oscillatory exchange coupling observed in magnetic multilayers of these materials. The spin dependence of the reflection probabilities is strong enough to give a large giant magnetoresistance even if there is no spin-dependent defect scattering. The calculated reflection amplitudes determine the strength of the oscillatory exchange coupling. ͓S0021-8979͑96͒79608-8͔

Multiscale approach to spin transport in magnetic multilayers

“…For instance, one can use multi-orbital (s, p, d...) models where each site of the TB model corresponds to an atom and where all the on site energies and hopping amplitudes are parametrized to reproduce ab-initio calculations. 73,74 When one is interested in transport properties however, one is not interested in a model that reproduces the entire band structure of a material, but only what happens around the Fermi level. Here, we take an even more limited approach: we construct our model such that it correctly reproduces the 5 characteristic length scales that were introduced in the previous section [mean free path for majority (l ↑ ) and minority (l ↓ ) electrons, spin-flip diffusion length (l sf ), transverse penetration length (l ⊥ ) and Larmor precession length (l L )].…”

Interface resistances of magnetic multilayers

“…28 Alternative ways of calculating reflection and transmission at a single specular interface have been used recently by Bruno 29 and Stiles. 30 Evaluation of Eq. ͑6͒ for ͑100͒ and ͑111͒ oriented Co/Cu multilayers yields interface resistances as summarized in Table I together with the values obtained from experiment.…”

Speed and efficiency of femtosecond spin current injection into a nonmagnetic material

“…Hence, the amount of spin moments that is lost in Ni, but not transferred to the Au substrate, is 0.27 ± 0.09 μ B /atom. The latter contributions are therefore spins that are lost either in Ni itself during the demagnetization process via, e.g., Elliott-Yafet spin-flip scattering, or spins that are initially part of the optically excited spin current in Ni but which are scattered directly at the Ni/Au interface [31].…”