title: Spin-dependent transparency of ferromagnet/superconductor interfaces.
abstract: We combine parameter-free calculations of the transmission and reflection matrices for clean and dirty interfaces with a scattering-theory formulation of Andreev reflection (AR) generalized to spin-polarized systems in order to critically evaluate the use of an extended Blonder-Tinkham-Klapwijk (BTK) model to extract values of the spin polarization for ferromagnetic metals from measurements of point-contact AR. Excellent agreement with the experimental conductance data is found for Pb/Cu but it is less good for Pb/Ni and poor for Pb/Co, indicating that the BTK formalism does not describe transport through superconducting/ferromagnetic interfaces correctly.
authors.affiliation: Faculty of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Xia
authors.forename: P J
authors.initials: PJ
authors.lastname: Kelly
authors.forename: G E W
authors.initials: GE
authors.lastname: Bauer
authors.forename: I
authors.initials: I
authors.lastname: Turek