Fabrication of a good-quality single grain YBCO sample through the control of seed crystals

1999 ◽  
Vol 35 (5) ◽  
pp. 4070-4072
Author(s):  
Chan-Joong Kim ◽  
Gye-Won Hong ◽  
Y.A. Jee ◽  
Young-Hee Han ◽  
Sang-Chul Han ◽  
...  
2004 ◽  
Vol 18 (1) ◽  
pp. 64-72 ◽  
Author(s):  
E Sudhakar Reddy ◽  
N Hari Babu ◽  
K Iida ◽  
T D Withnell ◽  
Y Shi ◽  
...  

2006 ◽  
Vol 21 (6) ◽  
pp. 1355-1362 ◽  
Author(s):  
Y. Shi ◽  
N. Hari Babu ◽  
K. Iida ◽  
D.A. Cardwell

We report the fabrication of Mg-doped NdBCO generic seed crystals, which have been developed recently for the fabrication of any rare earth (RE) based (RE)-Ba-Cu-O single-grain superconductor, with a wide range of Nd1+xBa2-xCu3-yMgyO7-δ compositions. Three basic characteristics of the seed crystals required for effective seeding of bulk (RE)BCO materials were studied in detail. We report the chemical, crystallographic, microstructural, and superconducting properties of the seeds and demonstrate clearly their potential to process various (RE)BCO superconductors in single-grain form. The melting point, volume fraction of Mg-rich inclusions in the bulk microstructure, and the chemical composition of the Nd1+xBa2-xCu3-yMgyO7-δ superconducting matrix of the seed crystals were studied as a function of initial MgO content. Finally, the suitable range of MgO-content within the generic seed crystal that controls effectively the orientation of the seeded grain without compromising its superconducting properties relative to those of the Mg-free compound is identified based on the wide range of seed crystal compositions investigated.


2002 ◽  
Vol 715 ◽  
Author(s):  
Sang-Hoon Jung ◽  
Jae-Hoon Lee ◽  
Min-Koo Han

AbstractA short channel polycrystalline silicon thin film transistor (poly-Si TFT), which has single grain boundary in the center of channel, is reported. The reported poly-Si TFT employs lateral grain growth method through aluminum patterns, which acts as a selective beam mask and a lateral heat sink during the laser irradiation, on an amorphous silicon layer. The electrical characteristics of the proposed poly-Si TFT have been considerably improved due to grain boundary density lowered. The reported short channel poly-Si TFT with single grain boundary exhibits high mobility as 222 cm2/Vsec and large on/off current ratio exceeding 1 × 108.


2019 ◽  
Author(s):  
Jennifer Gifford ◽  
◽  
Blake Oswell LaDouceur ◽  
William J. Davis ◽  
Shawn J. Malone
Keyword(s):  

2020 ◽  
Author(s):  
Vipin Kumar Singh ◽  
Sudipta Roy Barman
Keyword(s):  

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3216-3219 ◽  
Author(s):  
M. Ausloos ◽  
S. Dorbolo

A logarithmic behavior is hidden in the linear temperature regime of the electrical resistivity R(T) of some YBCO sample below 2T c where "pairs" break apart, fluctuations occur and "a gap is opening". An anomalous effect also occurs near 200 K in the normal state Hall coefficient. In a simulation of oxygen diffusion in planar 123 YBCO, an anomalous behavior is found in the oxygen-vacancy motion near such a temperature. We claim that the behavior of the specific heat above and near the critical temperature should be reexamined in order to show the influence and implications of fluctuations and dimensionality on the nature of the phase transition and on the true onset temperature.


2007 ◽  
Vol 558-559 ◽  
pp. 851-856 ◽  
Author(s):  
Takahisa Yamamoto ◽  
Teruyasu Mizoguchi ◽  
S.Y. Choi ◽  
Yukio Sato ◽  
Naoya Shibata ◽  
...  

SrTiO3 bicrystals with various types of grain boundaries were prepared by joining two single crystals at high temperature. By using the bicrystals, we examined their current-voltage characteristics across single grain boundaries from a viewpoint of point defect segregation in the vicinity of the grain boundaries. Current-voltage property in SrTiO3 bicrystals was confirmed to show a cooling rate dependency from annealing temperature, indicating that cation vacancies accumulate due to grain boundary oxidation. The theoretical results obtained by ab-initio calculation clearly showed that the formation energy of Sr vacancies is the lowest comparing with Ti and O vacancies in oxidized atomosphere. The formation of a double Schottky barrier (DSB) in n-type SrTiO3 is considered to be closely related to the accumulation of the charged Sr vacancies. Meanwhile, by using three types of low angle boundaries, the excess charges related to one grain boundary dislocation par unit length was estimated. In this study, we summarized our results obtained in our group.


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