  We provide compelling evidence to establish that, contrary to one's
elementary guess, the tunneling spin polarization (TSP) of amorphous CoFeB is
larger than that of highly textured fcc CoFeB. First principles atomic and
electronic structure calculations reveal striking agreement between the
measured TSP and the predicted s-electron spin polarization. Given the
disordered structure of the ternary alloy, not only do these results strongly
endorse our communal understanding of tunneling through AlOx, but they also
portray the key concepts that demand primary consideration in such complex
systems.
