Effect of crystallization of amorphous Fe5Co75Si4B16 alloy on its optical properties

The optical properties of ferromagnetic Fe₅Co₇₅Si₄B₁₆ alloy in the amorphous state and after temperature treatments have been investigated by spectroscopic ellipsometry in the energy range of 0.073–5.64 eV. It is shown that alloy crystallization changes significantly the frequency dependences of the optical constants and the dielectric functions calculated based on them. The atomic ordering is accompanied by a significant increase in the intensity of the fundamental band of quantum light absorption. The plasma and relaxation frequencies of conduction electrons have been calculated.