Spin-dependent transparency of ferromagnet/superconductor interfaces.
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.
Xia
K
K
Faculty of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Kelly
P J
PJ
Bauer
G E W
GE
Turek
I
I