Because the physical interpretation of the spin-polarization of a ferromagnet determined by point-contact Andreev reflection (PCAR) is non-trivial, we have carried out parameter-free calculations of PCAR spectra based upon a scattering-theory formulation of Andreev reflection generalized to spin-polarized systems and a tight-binding linear muffin tin orbital method for calculating the corresponding scattering matrices. PCAR is found to measure the spin-dependent interface transparency rather than the bulk polarization of the ferromagnet which is strongly overestimated by free electron model fitting.
@article{arxiv.cond-mat/0202515,
title = {Spin-dependent Transparency of Ferromagnet/Superconductor Interfaces},
author = {K. Xia and P. J. Kelly and G. E. W. Bauer and I. Turek},
journal= {arXiv preprint arXiv:cond-mat/0202515},
year = {2009}
}