Correlation between Magnetism and Spin-Dependent Transport in CoFeB Alloys

We report a correlation between the spin polarization of the tunneling electrons and the magnetic moment of amorphous CoFeB alloys. Such a correlation is surprising since the spin polarization of the tunneling electrons involves s-like electrons close to the Fermi level (EF), while the magnetic moment mainly arises due to all the d electrons below EF. We show that probing the s and d bands individually provides clear and crucial evidence for such a correlation to exist through s-d hybridization, and demonstrate the tunability of the electronic and magnetic properties of CoFeB alloys.