scholarly journals Combined iDPC and EELS analyses for quantifying oxygen vacancy concentration in LSMO

2021 ◽  
Vol 27 (S1) ◽  
pp. 1196-1197
Author(s):  
Aubrey Penn ◽  
Sanaz Koohfar ◽  
Divine Kumah ◽  
James LeBeau
Keyword(s):  
Oxygen Vacancy ◽  
Vacancy Concentration ◽  
Oxygen Vacancy Concentration

scholarly journals Effects on Microstructure and Ionic Conductivity of the Co-Doping with Strontium and Samarium of Ceria with Constant Oxygen Vacancy Concentration

Solids ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 341-370
Author(s):  
Toby Sherwood ◽  
Richard T. Baker
Keyword(s):  
Oxygen Vacancy ◽  
Grain Boundary ◽  
Vacancy Concentration ◽  
Synthesis Method ◽  
Ionic Conductivities ◽  
Solubility Limit ◽  
Material Structure ◽  
Oxygen Vacancy Concentration ◽  
Co Doping ◽  
Phase Pure

Partially substituted cerias are attractive materials for use as electrolytes in intermediate-temperature solid oxide fuel cells (SOFCs). Ceria doped with Sm or Gd has been found to have high ionic conductivities. However, there is interest in whether doping with multiple elements could lead to materials with higher ionic conductivities. The present study looks at the effects of co-doping Sr and Sm in ceria. A compositional series, Ce0.8+xSm0.2−2xSrxO2−δ (with x = 0–0.08), designed to have a constant oxygen vacancy concentration, was successfully prepared using the citrate–nitrate complexation method. A solubility limit of ~5 cation% Sr was found to impact material structure and conductivity. For phase-pure materials, with increasing Sr content, sinterability increased slightly and intrinsic conductivity decreased roughly linearly. The grain boundaries of phase-pure materials showed only a very small blocking effect, linked to the high-purity synthesis method employed, while at high %Sr, they became more blocking due to the presence of a SrCeO3 impurity. Grain capacitances were found to be 50–60 pF and grain boundary capacitances, 5–50 nF. The variation in the bulk capacitance with Sr content was small, and the variation in grain boundary capacitance could be explained by the variation in grain size. Slight deviations at high %Sr were attributed to the SrCeO3 impurity. In summary, in the absence of deleterious effects due to poor microstructure or impurities, such as Si, there is no improvement in conductivity on co-doping with Sr and Sm.

Magnetic State of Ba-Doped Manganites Depending on the Oxygen Vacancy Concentration

2002 ◽  
Vol 233 (2) ◽  
pp. 321-330 ◽  
Author(s):  
S.V. Trukhanov ◽  
N.V. Kasper ◽  
I.O. Troyanchuk ◽  
H. Szymczak ◽  
K. B�rner
Keyword(s):  
Oxygen Vacancy ◽  
Magnetic State ◽  
Vacancy Concentration ◽  
Oxygen Vacancy Concentration ◽  
Doped Manganites

MECHANISM STUDY ON OXYGEN VACANCY INDUCED RESISTANCE SWITCHING IN Au/LaMnO3/SrNb0.01Ti0.99O3

2013 ◽  
Vol 27 (11) ◽  
pp. 1350074 ◽  
Author(s):  
YU-LING JIN ◽  
ZHONG-TANG XU ◽  
KUI-JUAN JIN ◽  
CHEN GE ◽  
HUI-BIN LU ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Oxygen Vacancies ◽  
Vacancy Concentration ◽  
Resistance Switching ◽  
Switching Behavior ◽  
Oxygen Vacancy Concentration ◽  
Mechanism Study ◽  
Switching Performance ◽  
Switching Characteristics

Mechanism of resistance switching in heterostructure Au / LaMnO 3/ SrNb 0.01 Ti 0.99 O 3 was investigated. In Au / LaMnO 3/ SrNb 0.01 Ti 0.99 O 3 devices the LaMnO 3 films were fabricated under various oxygen pressures. The content of the oxygen vacancies has a significant impact on the resistance switching performance. We propose that the resistance switching characteristics of Au / LaMnO 3/ SrNb 0.01 Ti 0.99 O 3 arise from the modulation of the Au / LaMnO 3 Schottky barrier due to the change of the oxygen vacancy concentration at Au / LaMnO 3 interface under the external electric field. The effect of the oxygen vacancy concentration on the resistance switching is explained based on the self-consistent calculation. Both the experimental and numerical results confirm the important role of the oxygen vacancies in the resistance switching behavior.

scholarly journals Evoked Methane Photocatalytic Conversion to C2 Oxygenates over Ceria with Oxygen Vacancy

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 196 ◽  
Author(s):  
Jin Du ◽  
Wei Chen ◽  
Gangfeng Wu ◽  
Yanfang Song ◽  
Xiao Dong ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Photocatalytic Oxidation ◽  
Oxygen Vacancies ◽  
Vacancy Concentration ◽  
Direct Conversion ◽  
Oxygen Vacancy Concentration ◽  
Ambient Conditions ◽  
Ethanol Production Rate ◽  
Viable Approach ◽  
Oxidation By Water

Direct conversion of methane to its oxygenate derivatives remains highly attractive while challenging owing to the intrinsic chemical inertness of CH4. Photocatalysis arises as a promising green strategy which could stimulate water splitting to produce oxidative radicals for methane C–H activation and subsequent C–C coupling. However, synthesis of a photocatalyst with an appropriate capability of methane oxidation by water remains a challenge using an effective and viable approach. Herein, ceria nanoparticles with abundant oxygen vacancies prepared by calcinating commercial CeO2 powder at high temperatures in argon are reported to capably produce ethanol and aldehyde from CH4 photocatalytic oxidation under ambient conditions. Although high-temperature calcinations lead to lower light adsorptions and increased band gaps to some extent, deficient CeO2 nanoparticles with oxygen vacancies and surface CeIII species are formed, which are crucial for methane photocatalytic conversion. The ceria catalyst as-calcinated at 1100 °C had the highest oxygen vacancy concentration and CeIII content, achieving an ethanol production rate of 11.4 µmol·gcat−1·h−1 with a selectivity of 91.5%. Additional experimental results suggested that the product aldehyde was from the oxidation of ethanol during the photocatalytic conversion of CH4.

Effects of oxygen vacancy concentration and temperature on memristive behavior of SrRuO3/Nb:SrTiO3 junctions

2019 ◽  
Vol 28 (8) ◽  
pp. 087303 ◽  
Author(s):  
Zhi-Cheng Wang ◽  
Zhang-Zhang Cui ◽  
Hui Xu ◽  
Xiao-Fang Zhai ◽  
Ya-Lin Lu
Keyword(s):  
Oxygen Vacancy ◽  
Vacancy Concentration ◽  
Oxygen Vacancy Concentration ◽  
Memristive Behavior

scholarly journals Sol-Gel Processed Yttrium-Doped SnO2 Thin Film Transistors

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 254 ◽  
Author(s):  
Changmin Lee ◽  
Won-Yong Lee ◽  
Hyunjae Lee ◽  
Seunghyun Ha ◽  
Jin-Hyuk Bae ◽  
...  
Keyword(s):  
Thin Film ◽  
Oxygen Vacancy ◽  
Electrical Transport ◽  
Thin Film Transistors ◽  
Vacancy Concentration ◽  
Operation Mode ◽  
Sol Gel ◽  
Sno2 Thin Film ◽  
Oxygen Vacancy Concentration ◽  
Electrical Transport Properties

Y-doped SnO2 thin film transistors were successfully fabricated by means of sol-gel process. The effect of Y concentration on the structural, chemical, and electrical properties of sol-gel-processed SnO2 films was investigated via GIXRD, SPM, and XPS; the corresponding electrical transport properties of the film were also evaluated. The dopant, Y, can successfully control the free carrier concentration by suppressing the formation of oxygen vacancy inside SnO2 semiconductors due to its lower electronegativity and SEP. With an increase of Ywt%, it was observed that the crystallinity and oxygen vacancy concentration decreased, and the operation mode of SnO2 thin film transistor changed from accumulation (normally on) to enhancement mode (normally off) with a positive Vth shift.

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