Electronic structure of AgNbO3 and NaNbO3 studied by X-ray photoelectron spectroscopy

Kruczek, M.; Talik, E.; Kania, A.

doi:10.1016/j.ssc.2006.01.001

Cited by 52 publications

(31 citation statements)

References 23 publications

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“…They were identified and indexed in accordance with orthorhombic symmetry with space group Pbcm (ICDD catalogue No. 57) in agreement with literature data [15][16][17]. The determined lattice parameters values were a ¼ 5.501 Å , b ¼ 5.666 Å and c ¼ 15.520 Å .…”

Section: Structural and Chemical Characterisationsupporting

confidence: 88%

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Insulator–metal transition in Mn-doped NaNbO₃induced by chemical and thermal treatment

et al. 2008

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The transition between insulator and metal conductor states, induced by oxygen non-stoichiometry, was studied for NaNbO 3 : Mn crystals. Conditions for an optimal reduction were determined on the basis of TGA tests. The temperature dependencies of the resistance measured on the macroscale showed that the transition from thermally activated to metallic features depends on the level of oxygen deficiency. The LC-AFM measurement exhibited non-homogeneous electric resistance on the nanoscale. We ascribed the local insulator-metal transition to changeover in the electronic state of the Nb ions occurring in filaments. The Mn dopant stabilised the induced oxygen non-stoichiometry and the metallic conduction down to room temperature.

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Section: Structural and Chemical Characterisationsupporting

confidence: 88%

“…The single crystals of sodium niobate [15] and Mn-doped NN [13] were grown by the flux method. Transparent cubes and plates with dimensions of several millimetres were obtained.…”

Section: Methodsmentioning

confidence: 99%

Insulator–metal transition in Mn-doped NaNbO₃induced by chemical and thermal treatment

et al. 2008

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“…Ag 5s and Ag 5p cover the latter part of the conduction band from 12 eV to 22.67 eV (for AgNbO 3 ) and 11.50 eV to 22.5 eV (for AgTaO 3 ), which somewhat overlap but are not hybridized with B nd, as judged from the different band shape. It is found to be in agreement with the valence bands of AgNbO 3 single crystals and ceramics determined by xray photoemission spectroscopy (XPS) measurements of a valence band width of about 6.5 eV [19]. The valence bands are separated from the conduction bands at the symmetry point (Γ) by a direct gap of 2.933 eV for AgNbO 3 and 2.908 eV for AgTaO 3 .…”

Section: Band Structuresupporting

confidence: 83%

“…However, most of the papers devoted to AgBO 3 are focused on their structural and dielectric properties [13][14][15][16]. There are only a few studies of electronic structure of these compounds [17][18][19][38][39][40][41][42]. The electronic structure of valence bands, the band gap, and the low-energy conduction band determine the most important properties of the material in electronic device application.…”

Section: Introductionmentioning

confidence: 99%

First-principles studies of the electronic structure and optical properties of AgBO3 (B=Nb,Ta) in the paraelectric phase

Çabuk

Sımsek

2008

Open Physics

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Abstract:The electronic energy-band structure, density of states (DOS), and optical properties of AgBO 3 in the paraelectric cubic phase have been studied by using density functional theory within the local density approximation for exchange-correlation for the first time. The band structure shows a band gap of 1.533 eV (AgNbO 3 ) and 1.537 eV (AgTaO 3 ) at (M-Γ) point in the Brillouin zone. The optical spectra of AgBO 3 in the photon energy range up to 30 eV are investigated under the scissor approximation. The real and imaginary parts of the dielectric function and  thus the optical constants such as reflectivity, absorption coefficient, electron energy-loss function, refractive index, and extinction coefficient  are calculated. We have also made some comparisons with related experimental and theoretical data that is available.

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“…[1,3,32] EPR and XANES studies of NaNbO 3 :Mn crystals from the same batch [16,23À25] indicated the presence of the Mn 2C ionic state. It is worth noting that mixed ionic and covalent bonding occurs in the studied crystals [25] and the valence band is formed by O2p states hybridized with Nb4d and Mn3d states. [33] Even if the manganese ions would show a different ionic state, i.e.…”

Section: Pilch and A Molakmentioning

confidence: 99%

Resistance switching in rejuvenated NaNbO₃:Mn crystals

Pilch

Molak

2014

Phase Transitions

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In this paper, the resistance switching effect has been studied in NaNbO 3 :Mn crystals. Samples were rejuvenated in ambient air, below and above antiferroelectric phase transition. Dielectric spectroscopy has exhibited weak dispersion. The influence of annealing on the electronic structure has been determined with the use of X-ray photoelectron spectroscopy. Na2s, Nb3d, O1s, and Mn2p lines of the aged as-grown crystal and the rejuvenated samples spectra have been analyzed. Nb 4C states observed in the samples point to the presence of oxygen vacancies in the surface layer. Na ions migrate toward the surface due to rejuvenation. Switching from an insulator highresistance state to a semiconductor medium resistance and finally to a metallic-type low-resistance state has been observed. The results are discussed within the framework of the extended defects model. We propose that the aliovalent Mn 2C dopant ions stabilize the oxygen vacancies and enable the resistive switching.

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Electronic structure of AgNbO3 and NaNbO3 studied by X-ray photoelectron spectroscopy

Cited by 52 publications

References 23 publications

Insulator–metal transition in Mn-doped NaNbO₃induced by chemical and thermal treatment

Insulator–metal transition in Mn-doped NaNbO₃induced by chemical and thermal treatment

First-principles studies of the electronic structure and optical properties of AgBO3 (B=Nb,Ta) in the paraelectric phase

Resistance switching in rejuvenated NaNbO₃:Mn crystals

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Electronic structure of AgNbO3 and NaNbO3 studied by X-ray photoelectron spectroscopy

Cited by 52 publications

References 23 publications

Insulator–metal transition in Mn-doped NaNbO3induced by chemical and thermal treatment

Insulator–metal transition in Mn-doped NaNbO3induced by chemical and thermal treatment

First-principles studies of the electronic structure and optical properties of AgBO3 (B=Nb,Ta) in the paraelectric phase

Resistance switching in rejuvenated NaNbO3:Mn crystals

Contact Info

Product

Resources

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Insulator–metal transition in Mn-doped NaNbO₃induced by chemical and thermal treatment

Insulator–metal transition in Mn-doped NaNbO₃induced by chemical and thermal treatment

Resistance switching in rejuvenated NaNbO₃:Mn crystals