The Influence of Localized Electronic States on the Optical and Magneto-Optical Properties and Magnetoresistance in Amorphous CoFeNiSiB Alloys

摘要

The optical and magneto-optical properties of amorphous CoFeSiB ribbons were investigated for incident photons in the energy range from 0.05 to 2.2 eV. The Kerr rotation spectra for the amorphous films have a shape in the 0.6 - 2.2 eV region that is quite similar to that of bulk Co. The optical conductivity of the amorphous CoFe(Ni)SiB alloys increases slowly as a function of frequency (proportional toω~(1/3)) in the IR. Such aσ～ω~(1/3) dependence in the IR suggests an additional localization of the electron states. A large room-temperature magnetoresistance effect has been demonstrated in thin Co_(71)Fe_7Si_(12)B_(10) and Co_(59)Fe_5Ni_(10)Si_(11)B_(15) amorphous ribbons for alternating current at applied fields, H<80 Oe.