Luminescence from Defects and Impurity Centers in Y2O3

1989 ◽  
Vol 169 ◽  
Author(s):  
M. S. Jahan ◽  
D. W. Cooke ◽  
B. L Bennett ◽  
W. L Hults ◽  
M. A. Maez ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Resistance ◽  
High Temperature Superconductors ◽  
Emission Spectra ◽  
Second Phase ◽  
X Rays ◽  
Deep Traps ◽  
Impurity Ions ◽  
Order Of Magnitude ◽  
Impurity Centers

AbstractHigh-purity (99.999%) Y2O3 powder is used as a starting material for fabricating high-temperature superconductors (HTS), and is frequently found as an unreacted second phase in the final product. We have found that as-received Y2O3 contains Tb3+ paramagnetic impurity ions as determined by TSL and emission-spectra measurements. Deep luminescence traps (presumably Tb4+ ions) are formed in Y2O3 when it is exposed to frays, x rays, or fluorescent lights. These deep traps can only be removed by annealing the material to near 1600°C. Given the short coherence length of HTS it is possible that order-of-magnitude variations in the Tb impurity concentration of starting materials may affect the ultimate value of surface resistance (Rs).

Correlation of thermally stimulated luminescence with radio frequency surface resistance of high‐temperature superconductors

1989 ◽  
Vol 55 (10) ◽  
pp. 1038-1040 ◽  
Author(s):  
D. W. Cooke ◽  
B. Bennett ◽  
E. R. Gray ◽  
R. J. Houlton ◽  
W. L. Hults ◽  
...  
Keyword(s):  
High Temperature ◽  
Radio Frequency ◽  
Surface Resistance ◽  
High Temperature Superconductors ◽  
Thermally Stimulated Luminescence

Surface resistance of thin Perovskite films — high-temperature superconductors and giant magnetoresistance manganites

1996 ◽  
Vol 288 (1-2) ◽  
pp. 256-261 ◽  
Author(s):  
S.E. Lofland ◽  
M. Dominguez ◽  
S.D. Tyagi ◽  
S.M. Bhagat ◽  
M.C. Robson ◽  
...  
Keyword(s):  
High Temperature ◽  
Giant Magnetoresistance ◽  
Surface Resistance ◽  
High Temperature Superconductors

scholarly journals Электрополевой эффект в спектрах ЭПР центров Fe-=SUP=-3+-=/SUP=- и Mn-=SUP=-4+-=/SUP=- в тонких пластинках SrTiO-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (2) ◽  
pp. 224
Author(s):  
Б.Ф. Габбасов ◽  
А.А. Родионов ◽  
С.И. Никитин ◽  
В.А. Трепаков ◽  
Р.В. Юсупов
Keyword(s):  
Electric Field ◽  
Ground State ◽  
Applied Field ◽  
Field Effect ◽  
Electric Field Effect ◽  
Paramagnetic Resonance ◽  
Impurity Ions ◽  
Order Of Magnitude ◽  
Impurity Centers ◽  
Electron Paramagnetic

The results of the study of the electric field effect in the electron paramagnetic resonance spectra of the Fe3+ and Mn4+ impurity ions in thin oriented strontium titanate single-crystal plates are presented. The crystal structure of plates at T> 105 K turned out to be tetragonal, different from both the cubic and the antiferrodistortive tetragonal, inherent to SrTiO3 at T < 105 K. It is shown that for the studied centers, the electric field effect is quadratic in the applied electric field and has the same sign and order of magnitude, indicating the nonpolar origin of the observed high temperature tetragonal state. Analysis of the dependences of the axiality value on the applied field indicates that the electric field effect does not originate from the electrostriction and is due to the modification the wavefunction of the ground state of the impurity centers.

scholarly journals Calculations of Some Doping Nanostructurations and Patterns Improving the Functionality of High-Temperature Superconductors for Bolometer Device Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 97
Author(s):  
Jose C. Verde ◽  
Alberto S. Viz ◽  
Martín M. Botana ◽  
Carlos Montero-Orille ◽  
Manuel V. Ramallo
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
High Temperature Superconductors ◽  
Operational Parameters ◽  
Transition Edge ◽  
Saturation Power ◽  
Order Of Magnitude ◽  
Device Applications ◽  
Materials Used ◽  
Carrier Doping

We calculate the effects of doping nanostructuration and the patterning of thin films of high-temperature superconductors (HTS) with the aim of optimizing their functionality as sensing materials for resistive transition-edge bolometer devices (TES). We focus, in particular, on spatial variations of the carrier doping into the CuO 2 layers due to oxygen off-stoichiometry, (that induce, in turn, critical temperature variations) and explore following two major cases of such structurations: First, the random nanoscale disorder intrinsically associated to doping levels that do not maximize the superconducting critical temperature; our studies suggest that this first simple structuration already improves some of the bolometric operational parameters with respect to the conventional, nonstructured HTS materials used until now. Secondly, we consider the imposition of regular arrangements of zones with different nominal doping levels (patterning); we find that such regular patterns may improve the bolometer performance even further. We find one design that improves, with respect to nonstructured HTS materials, both the saturation power and the operating temperature width by more than one order of magnitude. It also almost doubles the response of the sensor to radiation.

THE SURFACE IMPEDANCE OF HIGH Tc SUPERCONDUCTORS

1989 ◽  
Vol 03 (01) ◽  
pp. 5-13 ◽  
Author(s):  
J. CARINI ◽  
L. DRABECK ◽  
G. GRÜNER
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Power Law ◽  
Surface Impedance ◽  
Low Temperatures ◽  
Qualitative Agreement ◽  
Surface Resistance ◽  
High Temperature Superconductors ◽  
High Tc Superconductors ◽  
High Tc

Recent experiments on the surface impedance of the high temperature superconductors are summarized. The overall temperature dependence of the penetration depth is in broad qualitative agreement with conventional pairing, but with an anomolous power law behavior observed at low temperatures. The surface resistance is orders of magnitude larger than estimates based on the Mattis-Bardeen theory. One possibility is unconventional pairing, but structural inhomogenities are the most likely explanation for the experimental results.

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