Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

scholarly journals Nanophosphors-Based White Light Sources

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1048 ◽  
Author(s):  
Maura Cesaria ◽  
Baldassare Di Bartolo
Keyword(s):  
Rare Earth ◽  
White Light ◽  
Volume Ratio ◽  
Light Sources ◽  
Co Doping ◽  
New Class ◽  
Luminescence Efficiency ◽  
Metal Doped ◽  
The Individual ◽  
The Impact

Miniaturization requests and progress in nanofabrication are prompting worldwide interest in nanophosphors as white-emission mercury-free lighting sources. By comparison with their bulk counterparts, nanophosphors exhibit reduced concentration quenching effects and a great potential to enhance luminescence efficiency and tunability. In this paper, the physics of the nanophoshors is overviewed with a focus on the impact of spatial confinement and surface-to-volume ratio on the luminescence issue, as well as rare earth-activated multicolor emission for white light (WL) output. In this respect, the prominently practiced strategies to achieve WL emission are single nanophosphors directly yielding WL by means of co-doping and superposition of the individual red, green, and blue emissions from different nanophosphors. Recently, a new class of efficient broadband WL emitting nanophosphors has been proposed, i.e., nominally un-doped rare earth free oxide (yttrium oxide, Y2O3) nanopowders and Cr transition metal-doped garnet nanocrystals. In regard to this unconventional WL emission, the main points are: it is strictly a nanoscale phenomenon, the presence of an emitting center may favor WL emission without being necessary for observing it, and, its inherent origin is still unknown. A comparison between such an unconventional WL emission and the existing literature is presented to point out its novelty and superior lighting performances.

scholarly journals Influence of Sample Pretreatment on the Analysis of High Contents of Rare-Earth and High Field Strength Elements in Geological Samples by ICP-AES and ICP-MS (Case Study of the Tomtor Deposit)

2020 ◽  
pp. 593-605
Author(s):  
Bagai-ool Yu. Saryg-ool ◽  
Lidiya N. Bukreeva ◽  
Irina N. Myagkaya ◽  
Aleksandr V. Tolstov ◽  
Elena V. Lazareva ◽  
...  
Keyword(s):  
Rare Earth ◽  
Field Strength ◽  
Inductively Coupled Plasma ◽  
High Field ◽  
Sample Pretreatment ◽  
Emission Spectrometry ◽  
Geological Samples ◽  
High Field Strength ◽  
Inductively Coupled ◽  
Icp Ms

Influence of sample pretreatment on the analysis of the high contents of rare earth (REE) and high field strength (HFSE) elements in geological samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) was studied. The rocks and rich ores of the Tomtor Nb-REE deposit were explored. Complete dissolution of the geological samples with a high content of “refractory” minerals has been achieved using fusion with a sodium peroxide. The results obtained by ICP-AES and ICP-MS after chemical dissolution are comparable with the results obtained by the XRF-SR without chemical pretreatment

scholarly journals Rare-Earth- and Uranium-Mesoionic Carbenes: A New Class of f-Block Carbene Complex Derived from an N-Heterocyclic Olefin

2017 ◽  
Vol 129 (38) ◽  
pp. 11692-11696 ◽  
Author(s):  
John A. Seed ◽  
Matthew Gregson ◽  
Floriana Tuna ◽  
Nicholas F. Chilton ◽  
Ashley J. Wooles ◽  
...  
Keyword(s):  
Rare Earth ◽  
Carbene Complex ◽  
New Class

Heterometallic Rare Earth/Group II Metal Chalcogenolate Clusters

1994 ◽  
Vol 116 (15) ◽  
pp. 6941-6942 ◽  
Author(s):  
M. Berardini ◽  
T. Emge ◽  
J. G. Breenan
Keyword(s):  
Rare Earth ◽  
Group Ii

scholarly journals High-field magnetization of rare-earth ions in scandium

1978 ◽  
Vol 17 (5) ◽  
pp. 2324-2327 ◽  
Author(s):  
L. W. Roeland ◽  
P. Touborg
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Rare Earth Ions ◽  
Field Magnetization ◽  
High Field Magnetization

A NEW EFFECT ON THE CRITICAL TEMPERATURE IN NON RARE EARTH CERAMIC SUPERCONDUCTORS

1988 ◽  
Vol 02 (05) ◽  
pp. 1079-1084
Author(s):  
J. Chela-Flores ◽  
P. Martin ◽  
J. J. Rodriguez Nuñez
Keyword(s):  
Rare Earth ◽  
Critical Temperature ◽  
Experimental Evidence ◽  
Rare Earth Oxide ◽  
Oxide Ceramics ◽  
Ceramic Superconductors

We argue from the experimental evidence that interlayer effects underlie the phenomenon of high- T c superconductivity in the non rare earth oxide ceramics.

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