Article
Chemistry, Physical
Jia Song, Shaochen Zhu, De Ning, Henny J. M. Bouwmeester
Summary: The structural evolution, electrical conductivity, oxygen nonstoichiometry, and oxygen transport properties of La1-xCaxFeO3-δ perovskite-type oxides were investigated. The results showed that Ca doping is mainly compensated by formation of electron holes rather than by oxygen vacancies, and oxygen vacancy diffusion coefficient and ionic conductivity increase with increasing Ca content in the compositions. The effective migration barrier for oxygen diffusion decreases with decreasing oxygen vacancy formation enthalpy.
JOURNAL OF MATERIALS CHEMISTRY A
(2021)
Article
Physics, Applied
D. Wei, X. N. Ying, X. M. Lu
Summary: The effect of lattice on charge ordering in La1/3Sr2/3FeO3-d is investigated by substituting calcium ions. Cation disorder caused by size differences between La3+, Sr2+, and Ca2+ ions on the A-site is observed in La-1/3(Sr1-xCax)(2/3)FeO3-d perovskite materials. Below room temperature, a charge ordering transition is detected using temperature dependent resistivity, differential scanning calorimeter, and mechanical spectroscopy. The transition temperature T-C of charge ordering transition is dependent on the variance of A-site cation radius distribution, indicating the important role of local lattice distortions. In comparison, octahedral tilting transitions above room temperature are identified using mechanical spectroscopy, and the transition temperatures are sensitive to the average cation radius. Finally, the significance of cation disorder effect is discussed by comparing with the case in manganates.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Ceramics
Lili Yang, Yongyong Li, Zhaoyu Hou, Caixia Shi, Guangjun Zhang, Fanrong Zeng, Juan Zhou, Shaorong Wang
Summary: This study focused on La1-xCaxFeO3-delta materials without Sr and Co as SOEC oxygen electrodes, with La0.6Ca0.4FeO3-delta (LCF64) showing excellent electrical conductivity and thermal expansion coefficient matching. The hydrogen electrode supported single cells prepared by tape casting and co-firing method exhibited good electrochemical performance in SOEC mode, with an electrolysis current density of 457.46 mA cm-2 at 800 degrees C. The SOEC showed an acceptable stable current density of approximately 280 mA cm(-2) for more than 60 hours during constant voltage electrolysis process.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Yadan Ren, Jun Oyama, Tomoki Uchiyama, Yuki Orikasa, Toshiki Watanabe, Kentaro Yamamoto, Tsuyoshi Takami, Yoshinori Nishiki, Shigenori Mitsushima, Yoshiharu Uchimoto
Summary: This study successfully observed the surface reconstruction of oxygen evolution reaction (OER) catalysts through the combination of ex situ and in situ techniques, confirming that surface reconstruction enhances the OER activity. This finding is of great significance for understanding the behavior of OER catalysts and can provide guidance for designing active catalysts.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
P. V. Jithin, Yugandhar Bitla, Manju Mishra Patidar, V. Ganesan, K. J. Sankaran, Joji Kurian
Summary: Temperature and magnetic field-dependent electrical and magnetic properties of La1-xCaxMnO3 (x = 0.4, 0.5) polycrystalline materials prepared by the sol-gel method are studied. The addition of Ca changes the crystallization phase structure and magnetic transition temperature of the material. The evolution of the Griffiths-like phase and the high magnetoresistance in the half-doped samples are also observed. Different theoretical models are used to explain the temperature-dependent transitions and magnetic field-dependent electrical transport behaviors.
JOURNAL OF NANOPARTICLE RESEARCH
(2023)
Article
Electrochemistry
A. R. Gilev, E. A. Kiselev, K. S. Sukhanov, D. V. Korona, V. A. Cherepanov
Summary: La2NiO4+delta, LCNF0604, LSNF0604, LSNF0605 and LSNF0504 compounds were synthesized by the citrate-nitrate technique and their phase purity was confirmed by X-ray powder diffraction. Electrochemical impedance spectroscopy studies showed that the polarization resistance decreased in the temperature range of 600-800 degrees C in wet air, with the order of LCNF0604>La2NiO4+delta>LSNF0504>LSNF0604>LSNF0605. The low frequency process was found to contribute significantly to the polarization resistance of the studied cells.
ELECTROCHIMICA ACTA
(2022)
Article
Materials Science, Ceramics
Yan Wang, Jianfei Xu, Shifeng Luo, Yan Bao, Jingwen Zhang, Cuiliu Han, Xinyu Yang, Jiuxing Zhang
Summary: Bulk La1-xSrxB6 hexaborides with high relative densities were fabricated using SPS and their phase composition, microstructure, mechanical and thermionic emission properties were investigated. The sintered specimens were found to be CsCl-type single-phase solid solutions without impurities or secondary phases. Homogenous elemental distributions of La and Sr were confirmed at both microscale and nanoscale. The sintered specimens exhibited higher Vickers hardness and comparable indentation fracture toughness compared to LaB6. Nanoindentation tests revealed high nanoindentation hardness and Young's moduli for the specimens. In terms of work function, bulk La1-xSrxB6 hexaborides showed lower work functions and higher thermionic emission current densities than LaB6, making them a potential class of excellent hot cathodes.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Taymaz Tabari, Marcin Kobielusz, Agnieszka Jarosz-Duda, Dheerendra Singh, Andrzej Kotarba, Artur Blachowski, Jiaguo Yu, Wojciech Macyk
Summary: Understanding the charge transfer mechanism in the straddle heterojunction architecture is crucial for designing active materials. The synthesis and thorough study of BiVO4, La1-xSrxFeO3-delta perovskites, and BiVO4@La1-xSrxFeO3-delta straddle heterojunction architectures addressed this issue. The insertion of Sr2+ ions into A-sites increased the Fe4+ ions at B-sites, strengthening the Fe-O bond and improving electrocatalytic activity. The increased Fermi levels reduced band bending and enhanced the drift direction of photoinduced charges, leading to significantly higher photocurrent in the heterojunction architecture.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
M. M. Sharma, Prince Sharma, Ganesh Gurjar, S. Patnaik, V. P. S. Awana
Summary: This study investigates the structural and physical properties of binary alloy Sn1-xSbx (x = 0.4, 0.5, 0.6) grown by the self-flux method, revealing their potential as candidates for topological superconductivity and confirming their type-II superconducting behavior at low temperatures.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Chemistry, Multidisciplinary
Ruben De Barros, Monica Ceretti, Wolfgang Schmidt, Vladimir Y. Pomjakushin, Werner Paulus
Summary: This work reports the growth and characterization of high-quality La2CoO4.25 single crystals for studying oxygen and electronic ordering phenomena. The crystals were grown without the addition of a solvent using the traveling solvent floating zone method. Post-synthesis annealing and various characterization techniques were used to confirm the composition, homogeneity, and crystalline quality of the crystals. The results revealed a complex structure and magnetic behavior involving oxygen ordering and antiferromagnetic ordering with a Neel temperature of 36K.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Physical
Rakesh Mondal, Neeraj Kumar Mishra, Mahatim Singh, Asha Gupta, Preetam Singh
Summary: The as-prepared La1-xKxCoO3-delta (0 <= x <= 0.5) exhibits excellent pseudocapacitive charge storage capacity and superior electrocatalytic activities. The introduction of oxygen ion defects enhances the performance of the material.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Condensed Matter
Umesh A. Palikundwar, Kalpana R. Nagde, Chandragupta M. Dudhe, Gautam C. Wakde
Summary: In this study, the structural, magnetic, and magneto transport properties of La1-ySryMn0.5Co0.5O3 +/-delta perovskites prepared by aqueous solution combustion synthesis were investigated. The effect of Sr doping on the properties of these perovskites was analyzed. X-ray diffraction was used to characterize the as-prepared perovskites for single phase formation. Magnetic study revealed an increase in ferromagnetic interactions at low temperatures in the doped compounds compared to the undoped compound. Resistivity measurements showed a reduction with Sr doping up to y = 0.5, attributed to enhanced ferromagnetic interactions and hopping probability of e(g) charge carriers due to high spin stabilized Co3+ ions.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Sumit Sarkar, Rajamani Raghunathan, Sourav Chowdhury, Ram Janay Choudhary, Deodatta Moreshwar Phase
Summary: This study investigates the mechanism of charge disproportionation in BaBiO3, finding that different hybridizations lead to different oxidation states in the material, validated through a combination of X-ray spectroscopic experiments and first-principle calculations. Additionally, the nature of charge disproportionation varies at room temperature and 200K.
Article
Physics, Applied
O. Quinn Carvalho, Prajwal Adiga, Le Wang, Jishan Liu, Endong Jia, Yingge Du, Slavomir Nemsak, Kelsey A. Stoerzinger
Summary: Nickel-containing perovskite oxides, such as LSNO, are highly active materials for the oxygen evolution reaction due to strong nickel-oxygen covalency. The addition of strontium enhances the affinity of LSNO surfaces for under-coordinated oxygen species, providing insights into the OER mechanisms mediated by oxygen vacancies. The study demonstrates the importance of surface composition in determining the OER activity of perovskite oxides.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Condensed Matter
Xindi Zhou, Xuenong Ying, Xiaomei Lu
Summary: In this study, perovskite La-0.64(Ba1-xCax)(0.36)FeO3-delta ( 0 <= x <= 0.4 $0 \leq x \leq 0.4$ ) samples were synthesized and investigated using X-ray diffraction and mechanical spectroscopy. The room-temperature structure of La0.64Ba0.36FeO3-delta is a mixture of orthorhombic and cubic phases. The calcium-doped La-0.64(Ba1-xCax)(0.36)FeO3-delta samples exhibit orthorhombic structure at room temperature. A modulus dip is observed in the La-0.64(Ba1-xCax)(0.36)FeO3-delta ( 0 <= x <= 0.4 $0 \leq x \leq 0.4$ ) samples above room temperature, indicating a phase transition from orthorhombic to rhombohedral structure with increasing temperature. The effects of oxygen nonstoichiometry on the room-temperature structure and phase transition are observed using mechanical spectroscopy.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
