Optical and Magneto-Optical Properties of Gd22Fe78 Thin Films in the Photon Energy Range From 1.5 to 5.5 eV

Abstract

Optical and magneto-optical properties of amorphous Gd22Fe78 (GdFe) thin films prepared by direct current (DC) sputtering on thermally oxidized substrates were characterized by the combination of spectroscopic ellipsometry and magneto-optical spectroscopy in the photon energy range from 1.5 to 5.5 eV. Thin SiNx and Ru coatings were used to prevent the GdFe surface oxidation and contamination. Using advanced theoretical models spectral dependence of the complete permittivity tensor and spectral dependence of the absorption coefficient were deduced from experimental data. No significant changes in the optical properties upon different coatings were observed, indicating reliability of used analysis.

Optical and magneto-optical properties of GdxFe(100-x) thin films close to the compensation point

“…7 imaginary parts of the off-diagonal elements ε 2i . The spectra are consistent with the spectral behavior of diagonal elements ε 1 and agree with previously reported results on Gd 22 Fe 78 19 . From Figs 6 and 7 one can see a change in the sign when crossing the compensation point.…”

“…The ε 1r spectra are dominated by one global minimum at 2.9 eV while the ε 1i amplitudes decrease at higher energies for all compositions. Obtained results show spectral behavior similar to previously published optical properties of Gd 22 Fe 78 19 , Fe, Gd 20,21 and Gd x Fe (100-x) 6,22 . The spectral dependence of ε 1r between 1.5 and 3 eV, where ε 1r decreases its amplitude with increasing energy, differs from typical Drude-like behavior (describing intra-band transitions) of metallic compounds, and is similar to the behavior of some transitions metals (including Cr, Gd, Ru, Ti 20,21 ).…”

“…Similarly to our previous work 19 , MOKE rotation and ellipticity spectra in the polar configuration were obtained using a method of generalized MO ellipsometry with rotating analyzer, which allowed the determination of the rotation angles with high accuracy. All the spectra were measured at the room temperature and nearly normal light incidence.…”

Advanced Materials and Device Architectures for Magnetooptical Spatial Light Modulators

“…Below Curie temperature T c the value of ε 3 is very close to ε 1 and above T c it is equal to ε 1 . With a restriction of low magnetic field and sticking to linear MO effects, it can be safely assumed ε 3 = ε 1 which simplifies the matrix to two, diagonal and off‐diagonal, elements . ε 1 is related to the regular refractive index n and extinction coefficient k .…”

“…Below Curie temperature T c the value of ε 3 is very close to ε 1 and above T c it is equal to ε 1 . With a restriction of low magnetic field and sticking to linear MO effects, it can be safely assumed ε 3 = ε 1 which simplifies the matrix to two, diagonal and off-diagonal, elements [88], [89], [90] . ε 1 is related to the regular refractive index n and extinction coefficient k. The off-diagonal elements are related to refractive indices n ± and extinction coefficients k ± of LHCP and RHCP light, and the magnitude of ε 2 indicates the strength of the MO response [91], [92] .…”