Effects of boron addition to the atomic structure and soft magnetic properties of FeCoB films

The magnetic, microwave, and the atomic structure properties of (Fe(0.7)Co(0.3))(1-x)B(x) sputtered films on glass substrates were investigated. The addition of boron induced a decrease in coercivity and ferromagnetic resonance linewidth. The amorphous structure was formed at x similar to 0.075. Extended x-ray absorption fine structure (EXAFS) of Fe and Co showed the reduced Fourier transform (FT) amplitude, and increased Debye-Waller factors as x was increased, indicating the increased disorder due to the thermal and structural displacements. Possible Fe-B bonding was observed with a reduced bond length, which indicates boron atoms' preference for staying in the interstitial sites in bcc unit cell. (c) 2008 American Institute of Physics.