Normal-State Infrared Anisotropy of Polycrystalline La1.85Sr0.15CuO4-y

1987 ◽  
Vol 99 ◽  
Author(s):  
G. L. Doll ◽  
J. Steinbeck ◽  
M. S. Dresselhaus ◽  
G. Dresselhaus ◽  
A. J. Strauss ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Crystal ◽  
Electronic Properties ◽  
Normal State ◽  
Superconducting State ◽  
Optical Anisotropy ◽  
Room Temperature ◽  
Reflectance Spectra ◽  
Frequency Range ◽  
Ir Studies

ABSTRACTBy examining the reflectance spectra of polycrystalline La1.85Sr0.15CuO4-y and La2NiO4-y in relation to the results of ir studies on single-crystal La2NiO4-y, we have determined the normal-state (room temperature) optical anisotropy of La1.85Sr0.15CuO4-y in the frequency range 40 cm-1 to 4800 cm-1. Vibrational and electronic properties corresponding to this anisotropy are examined, and a method is presented for extracting the optical properties of the superconducting state of La1.85Sr0.15CuO4-y.

Growth and Magneto-Optical Properties of CaTbAlO4 Crystal

2011 ◽  
Vol 306-307 ◽  
pp. 1722-1727 ◽  
Author(s):  
Man Mei ◽  
Li Li Cao ◽  
Yan He ◽  
Ru Ru Zhang ◽  
Fei Yun Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Crystal ◽  
Room Temperature ◽  
Near Infrared ◽  
Visible Region ◽  
Czochralski Method ◽  
Optical Devices ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectral

The calcium terbium aluminate (CaTbAlO4) single crystal was grown by Czochralski method successfully for the first time.The structure of the crystal was determined by X-ray diffraction analysis.The transmission spectrum of the crystal was measured at room temperature at the wavelength of 400-1500nm.The specific Faraday rotation of the single crystal was surveyed at room temperature at the wavelength 532nm, 633nm, and 1064nm respectively.The Verdet constants of the CaTbAlO4 crystal are calculated and the results show that the Verdet constants of CaTbAlO4 are around 110% higher than that of TGG in the visible and near-infrared spectral region.Therefore,crystal CaTbAlO4 can be promising material for the fabrication of magneto-optical devices in the visible region.

scholarly journals Optical Properties of Porous Silicon p-Si (100)

2019 ◽  
Vol 20 (3) ◽  
pp. 264-268
Author(s):  
P.O. Gentsar ◽  
M.V. Vuichyk ◽  
M.V. Isaev ◽  
P.O. Lischuk
Keyword(s):  
Optical Properties ◽  
Porous Silicon ◽  
Single Crystal ◽  
Pore Size ◽  
Band Gap ◽  
Spectral Range ◽  
Reflectance Spectra ◽  
Transmission Spectra

In this paper the reflectance spectra and transmission spectra of p-Si (100) porous silicon (PS) and silicon wires in the spectral range of 200 ÷ 1800 nm were investigated. Pore size of PS was 5 μm (lpor Si layer) and 50 μm (lpor Si layer) with porosity of 45 %, 55 % and 65 %. The length of silicon wires varies from 5.5 μm, to 50 μm with a porosity of 60 %. The decrease in the band gap of p-Si (100) porous silicon and silicon wires which grown on both sides of p-Si (100) as compared to the single crystal p-Si (100) is explained by the quantum-sized effect that occurs in the investigated objects.

Longitudinal Ultrasonic Attenuation in Tantalum at Frequencies up to 1 GHz

1971 ◽  
Vol 49 (3) ◽  
pp. 296-301 ◽  
Author(s):  
J. M. Perz ◽  
W. A. Roger
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Frequency Dependence ◽  
Normal State ◽  
Superconducting State ◽  
Ultrasonic Attenuation ◽  
Mean Free Path ◽  
Ultrasonic Waves ◽  
Frequency Range ◽  
Conduction Electrons

The attenuation due to interaction with conduction electrons of longitudinal sound propagating along [110] in a Ta crystal of resistance ratio 390 has been measured over the frequency range 0.46 to 1.0 GHz. The product of the wave vector q and the electronic mean free path l determined from the frequency dependence of the normal state attenuation ranges over 1.8 < ql < 3.8. The attenuation in the superconducting state in the absence of a magnetic field fits the BCS expression for 1.2 < T < Tc = 4.46 K with 2Δ(0) = 3.62 ± 0.06 kTc. The ultrasonic waves have been generated by thin film CdS transducers, and the conversion efficiency has been found to vary inversely with the active area of the transducer.

scholarly journals Room-temperature-superconducting Tc driven by electron correlation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hyun-Tak Kim
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Effective Mass ◽  
Coulomb Interaction ◽  
Electron Correlation ◽  
Normal State ◽  
Superconducting State ◽  
Room Temperature ◽  
Volume Contraction ◽  
Superconducting Tc

AbstractRoom-temperature-superconducting Tc measured by high pressure in hydrides can be theoretically explained by a Brinkman–Rice (BR)–Bardeen–Cooper–Schrieffer (BCS) Tc combining both the generalized BCS Tc and the diverging effective mass, m*/m = 1/(1 − (U/Uc)2), with the on-site Coulomb interaction U in the BR picture. A transition from U in a correlated metal of the normal state to Uc in the superconducting state can lead to superconductivity, which can be caused by volume contraction induced by high pressure or low temperature.

scholarly journals Influence of Bi on dielectric properties of GaAs1−xBix alloys

2019 ◽  
Vol 37 (2) ◽  
pp. 244-248 ◽  
Author(s):  
K. Ulutas ◽  
S. Yakut ◽  
D. Bozoglu ◽  
D. Deger ◽  
M. Arslan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dielectric Properties ◽  
Space Charge ◽  
Dielectric Spectroscopy ◽  
Room Temperature ◽  
Frequency Range ◽  
Dielectric Characterization ◽  
Ionic Polarization

AbstractPure GaAs and GaAs1−xBix alloys with different Bi ratios (1 %, 2.5 %, 3.5 %) fitted with silver contacts were measured with a dielectric spectroscopy device. Dielectric characterization was performed at room temperature in the frequency range of 0.1 Hz to 1 MHz. GaAs exhibits three relaxation regions corresponding to space-charge, dipolar and ionic polarizations in sequence with increasing frequency while GaAs1−xBix samples show only a broad dipolar polarization in the same frequency range. This result proves the filling of the lattice with Bi through making a new bonding reducing the influence of ionic polarization. This finding supports the previous results concerning optical properties of GaAs1−xBix, presented in the literature.

scholarly journals Absorption spectra of single-crystal and optical ceramics of fluorite in terahertz and infrared ranges

2019 ◽  
Vol 487 (1) ◽  
pp. 20-23
Author(s):  
G. A. Komandin ◽  
V. S. Nozdrin ◽  
P. P. Fedorov ◽  
V. V. Osiko
Keyword(s):  
Single Crystal ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Reflectance Spectra ◽  
Optical Characteristics ◽  
Transmission Spectra ◽  
Optical Ceramics ◽  
High Absorption

The transmission spectra of a single crystal, artificial and natural fluorite ceramics were recorded in the areas of material transparency in THz and the average IR range at room temperature. In the region of high absorption, the reflectance spectra were measured. Differences in the optical characteristics of a single crystal and optical ceramics are insignificant.

Electronic properties of particle-counting diamonds - Electronic properties of particle-counting diamonds I. Photoconductivity

1967 ◽  
Vol 262 (1126) ◽  
pp. 251-276 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Experimental Investigation ◽  
Optical Properties ◽  
Electronic Properties ◽  
Valence Band ◽  
Room Temperature ◽  
Energy Gap ◽  
Intrinsic Absorption ◽  
Particle Counting ◽  
Temperature Spectra

An account is given of an experimental investigation into the photoconductivity of particle-counting diamonds at room temperature and at 80 °K. Photoconduction spectra were obtained in the range 2500 to 200 nm which are typical of type la diamonds. The room temperature spectra are characterized by a system of eight photoconduction peaks. The peaks are attributed to the intrinsic absorption, the thermal decomposition of excitons and the excitation of three levels in the forbidden energy gap at 0-85, 1.45 and 2.2 eV from the valence band. This model is consistent with the known electro-optical properties of type la diamonds. The model is formulated mathematically and formally shown to predict the observed photoconduction responses of the diamonds to certain characteristic illuminations.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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