OPTICAL PROPERTIES OF THE BETA-PHASE ALLOYS AuZn, GuZn, AND PdIn

1967 ◽  
Vol 45 (8) ◽  
pp. 2505-2511 ◽  
Author(s):  
J.-P. Jan ◽  
S. S. Vishnubhatla
Keyword(s):  
Optical Properties ◽  
Optical Constants ◽  
Cesium Chloride ◽  
Beta Phase ◽  
The Other ◽  
Interband Transitions

The reflectance of β′-AuZn, β′-CuZn and β′-PdIn (cesium chloride structure) has been measured between 0.5 and 9 eV, and the other optical constants have been calculated by means of the Kramers–Kronig relations. The results can be explained in terms of interband transitions, the most important of which set in at 2.3, 2.4, and 2.3 eV respectively, and of intraband transitions. The possible occurrence of plasma resonances is discussed.

Electrical and Optical Properties of X2YZ (X = Co, Fe; Y = Cr, Mn, Ti; Z = Ga, Al, Si) Heusler Alloys

2010 ◽  
Vol 168-169 ◽  
pp. 545-548 ◽  
Author(s):  
K.A. Fomina ◽  
V. Marchenkov ◽  
E.I. Shreder ◽  
H.W. Weber
Keyword(s):  
Optical Properties ◽  
Heusler Alloys ◽  
Electronic States ◽  
Anomalous Behavior ◽  
The Other ◽  
Abnormal Behavior ◽  
Interband Transitions ◽  
Electrical And Optical Properties ◽  
Conduction Electrons ◽  
Experimental Data Analysis

We studied the electrical and optical properties of X2YZ (X = Co, Fe; Y = Cr, Mn, Ti; Z = Ga, Al, Si) Heusler alloys. We showed that the electrical and optical properties of Co2TiAl and Fe2TiAl are typical of metals. An abnormal behavior of the resistivity and the optical properties in the IR range of the other alloys was observed, i.e., the resistivity exhibits a semiconductor-like behavior and the optical conductivity has no contribution from the intraband absorption of the conduction electrons. The experimental data analysis, based on existing band calculations, allowed us to conclude that the anomalous behavior of their properties is determined by electronic states near to and at the Fermi level. The electronic states in the subband with spin up give the main contribution to the interband transitions in the IR range, but they practically do not contribute to the static conductivity (resistivity). There are almost no charge carries in the other electronic subband (with spin down), and hence, the interband transitions occur only at the energies above the semiconductor gap values.

Practical Correction of Three Fold Astigmatism in the Philips CM TEM

1996 ◽  
Vol 54 ◽  
pp. 418-419
Author(s):  
Arno J. Bleeker ◽  
Mark H.F. Overwijk ◽  
Max T. Otten
Keyword(s):  
Optical Properties ◽  
Phase Contrast ◽  
The Other ◽  
Objective Lens ◽  
Symmetric Part ◽  
A Posteriori ◽  
Contrast Transfer Function ◽  
High Brightness ◽  
Rotationally Symmetric ◽  
Brightness Field

With the improvement of the optical properties of the modern TEM objective lenses the point resolution is pushed beyond 0.2 nm. The objective lens of the CM300 UltraTwin combines a Cs of 0. 65 mm with a Cc of 1.4 mm. At 300 kV this results in a point resolution of 0.17 nm. Together with a high-brightness field-emission gun with an energy spread of 0.8 eV the information limit is pushed down to 0.1 nm. The rotationally symmetric part of the phase contrast transfer function (pctf), whose first zero at Scherzer focus determines the point resolution, is mainly determined by the Cs and defocus. Apart from the rotationally symmetric part there is also the non-rotationally symmetric part of the pctf. Here the main contributors are not only two-fold astigmatism and beam tilt but also three-fold astigmatism. The two-fold astigmatism together with the beam tilt can be corrected in a straight-forward way using the coma-free alignment and the objective stigmator. However, this only works well when the coefficient of three-fold astigmatism is negligible compared to the other aberration coefficients. Unfortunately this is not generally the case with the modern high-resolution objective lenses. Measurements done at a CM300 SuperTwin FEG showed a three fold-astigmatism of 1100 nm which is consistent with measurements done by others. A three-fold astigmatism of 1000 nm already sinificantly influences the image at a spatial frequency corresponding to 0.2 nm which is even above the point resolution of the objective lens. In principle it is possible to correct for the three-fold astigmatism a posteriori when through-focus series are taken or when off-axis holography is employed. This is, however not possible for single images. The only possibility is then to correct for the three-fold astigmatism in the microscope by the addition of a hexapole corrector near the objective lens.

Optical constants and electronic interband transitions of disordered GaAs1−xPx alloys

1998 ◽  
Vol 84 (7) ◽  
pp. 3696-3699 ◽  
Author(s):  
Kwang Joo Kim ◽  
Myoung Hee Lee ◽  
Jae Ho Bahng ◽  
Kyurhee Shim ◽  
B. D. Choe
Keyword(s):  
Optical Constants ◽  
Interband Transitions

Ellipsometric study of the complex optical constants of a CsPbBr3 perovskite thin film

2018 ◽  
Vol 6 (39) ◽  
pp. 10450-10455 ◽  
Author(s):  
Minglin Zhao ◽  
Yujun Shi ◽  
Jun Dai ◽  
Jie Lian
Keyword(s):  
Thin Film ◽  
Spectroscopic Ellipsometry ◽  
Optical Constants ◽  
Interband Transitions ◽  
Hybrid Perovskite ◽  
Ellipsometric Study

Complex optical constants and interband transitions of a hybrid perovskite CsPbBr3 thin film measured by spectroscopic ellipsometry.

scholarly journals Influence of Fe2O3 Dopant on Dielectric, Optical Conductivity and Nonlinear Optical Properties of Doped ZnO-Polystyrene Composites Films

2021 ◽  
Vol 12 (1) ◽  
pp. 170-179
Keyword(s):  
Optical Properties ◽  
Optical Conductivity ◽  
Electron Mobility ◽  
Relative Permittivity ◽  
Nonlinear Optical ◽  
The Other ◽  
Filler Concentration ◽  
Casting Method ◽  
Polystyrene Nanoparticles ◽  
Doped Zno

ZnO-Polystyrene nanoparticles doped with Fe2O3 were prepared by the casting method. Both Ed and Eo were calculated. εL and N/m* increase with filler concentrations for these samples. On the other hand, both M-1, M-3, decreased with increasing filler. The filler concentrations affected on determined values of both of ε\ and ε\\. These values increase with filler, and also the same result was achieved for both σ1 and σ2, which also increases with filler. The relation between VELF and SELF was determined. χ(1) increases with increasing filler ratio. n2, χ(3), βc, were determined theoretically. The electrical susceptibility χe and relative permittivity εr increase with the increase of filler concentration as a result of increasing electron mobility.

Optimization of Maximum VO2 Content in Polymorphous Oxides of Vanadium

2013 ◽  
Vol 538 ◽  
pp. 113-116 ◽  
Author(s):  
S.N. Svitasheva
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Optical Constants ◽  
Ellipsometric Method

Optical properties of thin films of vanadium thermally oxidized at air were studied by ellipsometric method using wavelength of He-Ne laser. Multipart composition of these films was revealed and method of optimization of technological conditions based on dynamic of changing optical constants near 68°C was developed.

Physical a priori solar radiation pressure models for GNSS satellites with the focus on BDS

2021 ◽  
Author(s):  
Bingbing Duan ◽  
Urs Hugentobler ◽  
Inga Selmke ◽  
Stefan Marz
Keyword(s):  
Optical Properties ◽  
Solar Radiation ◽  
Thermal Radiation ◽  
Radiation Pressure ◽  
Total Mass ◽  
A Priori ◽  
Solar Radiation Pressure ◽  
The Other ◽  
Time Range ◽  
Satellite Attitude

<p>A physical a priori box-wing solar radiation pressure (SRP) model is widely used by most analysis centers for Galileo and QZSS (Quasi-Zenith Satellite System) satellites, complemented by an ECOM or ECOM2 (Empirical CODE Orbit Model) model. For the other constellations, for instance GPS and GLONASS satellites, optical properties of satellite surfaces are not publicly available, especially for GPS Block IIF and GLONASS satellites. By fixing satellite surface areas and total mass to the values from some unpublished documents, we estimate satellite surface optical properties based on true GNSS measurements covering long time periods (typically this should be longer than a full beta angle time range to reduce correlations between parameters). Meanwhile, various physical effects are considered, such as yaw bias, radiator emission and thermal radiation of solar panels. We find that yaw bias of GPS Block IIA and IIR satellites does not dominate the Y-bias, it is likely that heat generated in the satellite is radiated from louvers or heat pipes on the Y side of the satellite. It is also noted that the ECOM Y0 estimates of both GPS and GLONASS satellites show clear anomaly during eclipse seasons. This indicates that the radiator emission is present when the satellite crosses shadows. Since satellite attitude during eclipse seasons could be different from the nominal yaw, potential radiator effect in the –X surface could be wrongly absorbed by the ECOM Y0 as well. By considering all the estimated parameters in an a priori model we observe clear improvement in satellite orbits, especially for GLONASS satellites. China’s Beidou-3 satellites are now providing PNT (positioning, navigation and timing) service globally. Satellite attitude, dimensions and total mass are publicly available. Also, the absorption optical properties of each satellite surface are given. With all this information, we estimate the other optical properties of Beidou satellites considering similar yaw bias, radiator and thermal radiation effects as those in GPS and GLONASS satellites.</p>

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