Study of optical properties and electronic structure of ferromagnetic FeCo

The optical properties of ordered cubic FeCo were investigated by spectroscopic ellipsometry in the 1.5-5.5 eV photon energy region at room temperature. A strong absorption structure exists around 2 eV in the optical conductivity spectrum of the compound, which is located close to that of pure bcc Fe. The spin-polarized band structure of FeCo calculated by the linear-muffin-tin orbitals method shows that the d-states from Co sites disperse in the same energy region as those from Fe sites, The calculated real part of the optical conductivity of FeCo from its band structure exhibits a strong absorption structure around 2 eV in good agreement with the experimental spectrum. Such agreement indicates a dispersive character of the d-bands of FeCo comparable to those of pure Fe. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.