Determination of manganese valency in La1−xSrxMnO3 using ELNES in the (S)TEM

Riedl, Thomas; Gemming, Thomas; Gruner, W.; Acker, Jörg; Wetzig, K.

doi:10.1016/j.micron.2006.06.017

Cited by 40 publications

(26 citation statements)

References 26 publications

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“…Furthermore, the first main resonance, which results from excitation into hybridized states containing Pr 5d and Ca 3d contributions [20], shifts from 534 eV (x Ca = 0) to 536.4 eV (x Ca = 0.8), which is in good agreement with data reported on various Sr-and Ca-doped rare-earth manganites [11,13]. These trends can be expressed as an increasing energetic distance ΔE K between the pre-edge feature and the first main resonance (Table 1), which reflects the effects of the hole doping [16].…”

Section: Doping Dependence Of Virgin Samplessupporting

confidence: 89%

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In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts

et al. 2014

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Studying catalysts in situ is of high interest for understanding their surface structure and electronic states in operation. Herein, we present a study of epitaxial manganite perovskite thin films (Pr 1−x Ca x MnO 3 ) active for the oxygen evolution reaction (OER) from electro-catalytic water splitting. X-ray absorption near-edge spectroscopy (XANES) at the Mn L-and O K-edges, as well as X-ray photoemission spectroscopy (XPS) of the O 1s and Ca 2p states have been performed in ultra-high vacuum and in water vapor under positive applied bias at room temperature. It is shown that under the oxidizing conditions of the OER a reduced Mn 2+ species is generated at the catalyst surface. The Mn valence shift is accompanied by the formation of surface oxygen vacancies. Annealing of the catalysts in O 2 atmosphere at 120 °C restores the virgin surfaces.

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Section: Doping Dependence Of Virgin Samplessupporting

confidence: 89%

“…According to Riedl et al [16] our data quantitatively represent the expectation of a systematic Mn valence increase between 3+ and 4+. The pre-edge region of the O K-edge at roughly 530 eV ( Figure 1b) represents excitation into hybridized states containing O 2p and Mn 3d states [17,18].…”

Section: Doping Dependence Of Virgin Samplessupporting

confidence: 84%

In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts

et al. 2014

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“…While EDS mapping typically shows a homogeneous distribution of the Mn, O and Na over individual crystals (Figure 1 Furthermore, the manganese L 2,3 core-loss EEL spectrum of the Na-birnessite was recorded ( Figure S2) and carefully analyzed based on the white line ratio method [29]. According to this method, the integral intensity ratio of the L 3 and L 2 excitation peaks of a transition metal is correlated to its formal oxidation state [29][30][31][32][33][34][35]. The analysis resulted in the average oxidation state of 3.4, postulating a mixed valent (Mn 3+ /Mn 4+ ) character for the manganese cations.…”

Section: A Transmission Electron Microscopy Studies (Eds Hrtem Eels)mentioning

confidence: 99%

Hydration-induced spin-glass state in a frustrated Na-Mn-O triangular lattice

et al. 2016

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Birnessite compounds are stable across a wide range of compositions that produces a remarkable diversity in their physical, electrochemical and functional properties. These are hydrated analogues of the magnetically frustrated, mixed-valent manganese oxide structures, with general formula, Na x MnO 2 . Here we demonstrate that the direct hydration of layered rock-salt type α-NaMnO 2 , with the geometrically frustrated triangular lattice topology, yields the birnessite type oxide, Na 0.36 MnO 2 ·0.2H 2 O, transforming its magnetic properties. This compound has a muchexpanded interlayer spacing compared to its parent α-NaMnO 2 compound. We show that while the parent α-NaMnO 2 possesses a Néel temperature of 45 K as a result of broken symmetry in the Mn 3+ sub-lattice, the hydrated derivative undergoes collective spin-freezing at 29 K within the Mn 3+ /Mn 4+ sub-lattice. Scaling-law analysis of the frequency dispersion of the AC susceptibility, as well as the temperature-dependent, low-field DC magnetization confirm a cooperative spin-glass state of strongly interacting spins. This is supported by complementary 2 spectroscopic analysis (HAADF-STEM, EDS, EELS) as well as by a structural investigation (high-resolution TEM, X-ray and neutron powder diffraction) that yield insights into the chemical and atomic structure modifications. We conclude that the spin-glass state in birnessite is driven by the spin-frustration imposed by the underlying triangular lattice topology that is further enhanced by the in-plane bond-disorder generated by the mixed-valent character of manganese in the layers.

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“…Moreover, the information about valence‐ and conduction‐band electronic properties, surface properties, chemical bonding, and element‐specific pair distance distribution functions can be also obtained by the EELS method . EELS has the ability to fingerprint the same element in different forms, which is a strong advantage over EDX . In situ STEM imaging and EELS were used by Gu et al to probe the chemical and structural evolution of SnO 2 nanowire anode in NIBs .…”

Section: Novel Methods For Sodium‐ion Battery Materialsmentioning

confidence: 99%

“…[219] EELS has the ability to fingerprint the same element in different forms, which is a strong advantage over EDX. [220] In situ STEM imaging and EELS were used by Gu et al to probe the chemical and structural evolution of SnO 2 nanowire anode in NIBs. [217] Figure 18a shows the Z-contrast image of the reaction in front of a nanowire, featuring the crystalline SnO 2 covered by Na 2 O, in which Na x Sn shows a higher brightness.…”

Section: Electron Energy-loss Spectroscopymentioning

confidence: 99%

Novel Methods for Sodium‐Ion Battery Materials

Zhao

et al. 2017

Small Methods

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Sodium‐ion batteries (NIBs) as an ideal candidate for large‐scale energy‐storage systems (ESSs) have been the subject of extensive attention worldwide as a result of the ever‐growing energy demands. Development of advanced NIB techniques with potentially higher performance is of great concern to meet the requirements of ESSs. Based on modern material characterization methods and technological optimizations, the systematic understanding of rechargeable batteries has been further developed. Novel methods for NIB materials could provide a rational guideline for the fundamental understanding and practical optimization of battery systems. Here, the focus is mainly on a discussion of novel or fresh experimental methods and characterization techniques for NIB materials from the relationships between properties and performances, which are roughly classified into four parts: structure‐related techniques, composition‐related techniques, size‐ and morphology‐related techniques, and surface‐ and interface‐related techniques. Respective detection mechanisms of each method will be discussed, and special attention is paid to examples of these characterization techniques for NIB devices. It is hoped that by the study of NIB‐related details, a certain reference to the development of advanced materials can be provided.

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Determination of manganese valency in La1−xSrxMnO3 using ELNES in the (S)TEM

Cited by 40 publications

References 26 publications

In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts

In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts

Hydration-induced spin-glass state in a frustrated Na-Mn-O triangular lattice

Novel Methods for Sodium‐Ion Battery Materials

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