“…The second Lorentz oscillator centered near 2.5 eV does not significantly modify the spectral dependence of Drude behavior due to its small amplitude. This points on the origin of Gd d-d electron transition 23,24 , since this transition should be forbidden with small oscillator strength.Figure 2Real parts of diagonal elements of the permittivity tensor of the Gd x Fe (100-x) thin films.Figure 3Imaginary parts of diagonal elements of the permittivity tensor of the Gd x Fe (100-x) thin films. The inset displays the dependence of the imaginary parts on Gd concentration at E = 2.8 eV.…”
Section: Resultsmentioning
confidence: 97%
“…The Fe 3d state lie around 1.5 eV below Fermi energy, while Gd 5d states are situated approx. 0.5 eV above the Fermi energy 23,24 . The second Lorentz oscillator centered near 2.5 eV does not significantly modify the spectral dependence of Drude behavior due to its small amplitude.…”
Unlike ferromagnetic materials, ferrimagnetic metals have recently received considerable attention due to their bulk perpendicular magnetic anisotropy, low net magnetization and tunable magnetic properties. This makes them perfect candidates for the research of recently discovered spin-torque related phenomena. Among other ferrimagnetic metals, GdFe has an advantage in relatively large magnetic moments in both sublattices and tunability of compensation point above the room temperature by small changes in its composition. We present a systematic study of optical and magneto-optical properties of amorphous GdxFe(100-x) thin films of various compositions (x = 18.3, 20.0, 24.7, 26.7) prepared by DC sputtering on thermally oxidized SiO2 substrates. A combination of spectroscopic ellipsometry and magneto-optical spectroscopy in the photon energy range from 1.5 to 5.5 eV with advanced theoretical models allowed us to deduce the spectral dependence of complete permittivity tensors across the compensation point. Such information is important for further optical detection of spin related phenomena driven by vicinity of compensation point in nanostructures containing GdFe.
“…The second Lorentz oscillator centered near 2.5 eV does not significantly modify the spectral dependence of Drude behavior due to its small amplitude. This points on the origin of Gd d-d electron transition 23,24 , since this transition should be forbidden with small oscillator strength.Figure 2Real parts of diagonal elements of the permittivity tensor of the Gd x Fe (100-x) thin films.Figure 3Imaginary parts of diagonal elements of the permittivity tensor of the Gd x Fe (100-x) thin films. The inset displays the dependence of the imaginary parts on Gd concentration at E = 2.8 eV.…”
Section: Resultsmentioning
confidence: 97%
“…The Fe 3d state lie around 1.5 eV below Fermi energy, while Gd 5d states are situated approx. 0.5 eV above the Fermi energy 23,24 . The second Lorentz oscillator centered near 2.5 eV does not significantly modify the spectral dependence of Drude behavior due to its small amplitude.…”
Unlike ferromagnetic materials, ferrimagnetic metals have recently received considerable attention due to their bulk perpendicular magnetic anisotropy, low net magnetization and tunable magnetic properties. This makes them perfect candidates for the research of recently discovered spin-torque related phenomena. Among other ferrimagnetic metals, GdFe has an advantage in relatively large magnetic moments in both sublattices and tunability of compensation point above the room temperature by small changes in its composition. We present a systematic study of optical and magneto-optical properties of amorphous GdxFe(100-x) thin films of various compositions (x = 18.3, 20.0, 24.7, 26.7) prepared by DC sputtering on thermally oxidized SiO2 substrates. A combination of spectroscopic ellipsometry and magneto-optical spectroscopy in the photon energy range from 1.5 to 5.5 eV with advanced theoretical models allowed us to deduce the spectral dependence of complete permittivity tensors across the compensation point. Such information is important for further optical detection of spin related phenomena driven by vicinity of compensation point in nanostructures containing GdFe.
“…using all-electron full-potential linear muffin-tin orbital method with GGA+U. 30 The magnetic moment for Co is calculated as 1.286B, compared with the value of 1.175B reported by B.…”
Section: Electronic Structure Of Mgcu2-type Gdco2mentioning
confidence: 96%
“…Previous experimental and theoretical studies of MgCu2-type GdX2 (X = Fe, Co, Ni) compounds have shown that the individual Gd magnetic moments are ferromagnetically coupled, so Gd was treated in the same way in these calculations. [30][31][32] The magnetic moment on each Gd in GdCo2 is calculated by LSDA+U (, parameters set tofor Gd: U = 6.70 eV and J = 0.70 eV, 37 ) as 7.405B compared to 7.433B, which was calculated by B. Zegaou et al…”
Section: Electronic Structure Of Mgcu2-type Gdco2mentioning
Gd(Co1-xGax)2 (x = 0, 1/6, 1/3, 1/2, 2/3, 5/6, and 1) phases were synthesized by arc melting the constituent elements and subsequent annealing. The samples were characterized by powder and single crystal X-ray diffraction, magnetic measurements, and electronic structure calculations. An interesting structural sequence was obtained: cubic MgCu2-type structure for x = 0 and 1/6; MgZn2-type structure for x = 1/3; orthorhombic SrMgSi-type structure for x = ½; orthorhombic CeCu2-type structure for x = 2/3; hexagonal AlB2-type structure for x = 5/6 and 1.Tight-binding linear-muffin-tin orbital (TB-LMTO) calculations were performed on GdCo2, GdCoGa, and GdGa2 to trace the origin of their structural transformations, which appear to be driven by the changes in the valence electron count (VEC). In addition, some conclusions of these fully stoichiometric compounds were obtained from the rigid band model. GdGa2 (x = 1) is antiferromagnetic, while the other ones are either ferrimagnetic or ferromagnetic. TC of Gd(Co1-xGax)2 decreases monotonically with the increasing Ga content, suggesting that promising room temperature (RT) magnetocaloric materials could be obtained between x = 1/6 and x = 1/3.
“…Для интерметаллидов GdFe 2 и LuFe 2 рядом авторов были выполнены вычисления электронной структуры [12][13][14][15][16][17][18][19], показавшие, что вблизи уровня Ферми происходит сильная гибридизация широких 3d-зон железа и 5d-зон редкоземельного металла, тогда как 4 f -зоны Gd и Lu локализованы в узких областях энергий. На основе таких расчетов были интерпретированы результаты по исследованию фотоэмиссии и поглощения рент-геновского излучения [20][21][22].…”
The optical properties of binary GdFe_2 and LuFe_2 compounds are studied by the ellipsometric method in the 0.22–17 μm spectral range. A number of spectral and electronic characteristics are determined. The experimental dependences of optical conductivity in the light quantum absorption region are interpreted based on previously published calculations of electronic states densities.
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