Study of the Effect of Oxygen Annealing on YBCO Platelet Aggregates Synthesized by a Biomimetic Method

2013 ◽  
Vol 834-836 ◽  
pp. 437-441
Author(s):  
Zi Li Zhang ◽  
Hong Li Suo ◽  
Ahmed Kursumovic ◽  
Min Liu ◽  
Yi Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Deficiency ◽  
Superconducting Transition ◽  
Oxygen Annealing ◽  
High Temperature Anneal ◽  
Structural And Electrical Properties ◽  
Platelet Aggregates ◽  
Biomimetic Method ◽  
Pre Treatment ◽  
Effect Of Oxygen

The effect of different oxygen annealing treatments on the structural and electrical properties of samples of the high temperature superconductor YBa2Cu3O7δ(YBCO) synthesized by a biomimetic method has been studied. By oxygen annealing, the oxygen deficiency resulting from the synthesis in air can be adequately compensated. A two-stage annealing process including a high temperature step results in a sharper superconducting transition and higher critical current density of the YBCO than annealing only at low temperature, due to the additional elimination of carbon residues from the biopolymer additive. To avoid the formation of impurity phases resulting from decomposition of the YBCO during the high-temperature anneal, careful pre-treatment by rinsing the as-synthesized YBCO with distilled water to remove residual NaCl is necessary.

Effect of oxygen deficiency reduction in Mg-doped Mn-spinel on its cell storage performance at high temperature

2006 ◽  
Vol 51 (25) ◽  
pp. 5508-5514 ◽  
Author(s):  
Michio Takahashi ◽  
Toshihiro Yoshida ◽  
Akimasa Ichikawa ◽  
Kenshin Kitoh ◽  
Hiroyuki Katsukawa ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Deficiency ◽  
Storage Performance ◽  
Effect Of Oxygen ◽  
Cell Storage ◽  
Mg Doped

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

Defect Complexes and Non-Equilibrium Processes Underlying the P-Type Doping of GaN

1998 ◽  
Vol 537 ◽  
Author(s):  
Fernando A. Reboredo ◽  
Sokrates T. Pantelides
Keyword(s):  
High Temperature ◽  
Experimental Evidence ◽  
First Principles ◽  
Final Anneal ◽  
First Principles Calculations ◽  
Defect Complexes ◽  
Equilibrium Processes ◽  
Open Questions ◽  
High Temperature Anneal ◽  
P Type

AbstractIt is well known that hydrogen plays a key role in p-type doping of GaN. It is believed that H passivates substitutional Mg during growth by forming a Mgs-N-Hi complex; in subsequent annealing, H is removed, resulting in p-type doping. Several open questions have remained, however, such as experimental evidence for other complexes involving Mg and H and difficulties in accounting for the relatively high-temperature anneal needed to remove H. We present first principles calculations in terms of which we show that the doping process is in fact significantly more complex. In particular, interstitial Mg plays a major role in limiting p-type doping. Overall, several substitutional/interstitial complexes form and can bind H, with vibrational frequencies that account for hitherto unidentified observed lines. We predict that these defects, which limit doping efficiency, can be eliminated by annealing in an atmosphere of H and N prior to the final anneal that removes H.

Oxygen Precipitation in Conventional and Nitrogen Co-Doped Heavily Arsenic-Doped Czochralski Silicon Crystals: Oswald Ripening

2009 ◽  
Vol 156-158 ◽  
pp. 275-278
Author(s):  
Xiang Yang Ma ◽  
Yan Feng ◽  
Yu Heng Zeng ◽  
De Ren Yang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Czochralski Silicon ◽  
Silicon Crystals ◽  
Oxygen Precipitation ◽  
High Temperature Anneal ◽  
Oxygen Precipitates ◽  
Co Doped ◽  
Oswald Ripening

Oxygen precipitation (OP) behaviors in conventional and nitrogen co-doped heavily arsenic-doped Czocharalski silicon crystals subjected to low-high two-step anneals of 650 oC/8 h + 1000 oC/4-256 h have been comparatively investigated. Due to the nitrogen enhanced nucleation of OP during the low temperature anneal, much higher density of oxygen precipitates generated in the nitrogen co-doped specimens. With the extension of high temperature anneal, Oswald ripening of OP in the nitrogen co-doped specimens preceded that in the conventional ones. Moreover, due to the Oswald ripening effect, the oxygen precipitates in the conventional specimens became larger with a wider range of sizes. While, the sizes of oxygen precipitates in the nitrogen co-doped specimens distributed in a much narrower range with respect to the conventional ones.

Improvement of Minority Carrier Lifetime in Thick 4H-SiC Epi-layers by Multiple Thermal Oxidations and Anneals

2013 ◽  
Vol 1538 ◽  
pp. 329-333 ◽  
Author(s):  
Lin Cheng ◽  
Michael J. O’Loughlin ◽  
Alexander V. Suvorov ◽  
Edward R. Van Brunt ◽  
Albert A. Burk ◽  
...  
Keyword(s):  
High Temperature ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Power Devices ◽  
Oxidation Treatment ◽  
Temperature Oxidation ◽  
Oxidation Step ◽  
High Temperature Anneal ◽  
Lifetime Enhancement

ABSTRACTThis paper details the development of a technique to improve the minority carrier lifetime of 4H-SiC thick (≥ 100 μm) n-type epitaxial layers through multiple thermal oxidations. A steady improvement in lifetime is seen with each oxidation step, improving from a starting ambipolar carrier lifetime of 1.09 µs to 11.2 µs after 4 oxidation steps and a high-temperature anneal. This multiple-oxidation lifetime enhancement technique is compared to a single high-temperature oxidation step, and a carbon implantation followed by a high-temperature anneal, which are traditional ways to achieve high ambipolar lifetime in 4H-SiC n-type epilayers. The multiple oxidation treatment resulted in a high minimum carrier lifetime of 6 µs, compared to < 2 µs for other treatments. The implications of lifetime enhancement to high-voltage/high-current 4H-SiC power devices are also discussed.

High-temperature phases of YBa2Cu3O6+x related to the superconducting transition

1988 ◽  
Vol 7 (5) ◽  
pp. 489-492 ◽  
Author(s):  
L. Papadimitriou ◽  
O. Valassiades ◽  
K. Manolikas ◽  
J. Stoemenos ◽  
J. Spyridelis ◽  
...  
Keyword(s):  
High Temperature ◽  
Superconducting Transition
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