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Vračar, Miloš; Kuzmin, Alexei; Merkle, Rotraut; Purans, J.; Kotomin, E. A.; Maier, Joachim; Mathon, O.

doi:10.1103/physrevb.76.174107

Cited by 133 publications

(127 citation statements)

References 60 publications

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“…In any case, the presence of vacancies associated with dopant sites is not sufficient to create enough asymmetry breaking and give rise to first-order Raman peaks. 40 The presence of such Raman peaks indicates the presence of local symmetry reduction for BZY and even undoped BZ. While on a long-range scale undoped BZ is undoubtely a cubic perovskite, the presence of Raman peaks indicates that some local distortions also occur.…”

Section: Discussionmentioning

confidence: 99%

“…A previous study on Fe:SrTiO 3 showed that the mere presence of oxygen vacancies and an aliovalent dopant at the B site in the perovskite do not lead to additional peaks. 40 For this reason, we propose that the Raman peaks in Y-doped BZ are due to the tilting of the YO 6 octahedra, which represent a permanent local symmetry lowering, as opposed to the transient or incoherent symmetry lowering due to anion sublattice motion in undoped BZ. The tilted YÀOÀM configurations were predicted by DFT calculations for 12.5% Y-doped BZ.…”

Section: Discussionmentioning

confidence: 99%

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Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO₃

et al. 2011

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Yttrium-doped barium zirconate (BZY) is the most promising candidate for proton-conducting ceramics and has been extensively studied in recent years. The detailed features of the crystal structure, both short-range and long-range, as well as the crystal chemistry driving the doping process, are largely unknown. We use very high resolution X-ray diffraction (HR-XRD) to resolve the crystal structure, which is very slightly tetragonally distorted in BZY, while the local environment around Zr4+ and Y3+ is probed with extended X-ray absorption fine structure (EXAFS), and the symmetry and vibrations are investigated by using Raman spectroscopy. It is found that barium zirconate shows some degree of local deviation from the cubic arystotype even if undoped, which upon substitution by the perceptibly larger Y3+, playing the role of a rigid inclusion, is further increased. This distortion is one limiting factor concerning the Y3+ solubility. The effects are correlated to the proton conduction properties of BZY

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO₃

et al. 2011

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“…A muffin-tin cluster potential was calculated in a self-consistent way, and the complex Hedin-Lundqvist exchange-correlation potential was used to account for inelastic effects (see the details in ref. 17). Experimental backscattering phases and amplitudes were extracted from the experimental EXAFS data measured on a polycrystalline LaFeO 3 powder at room temperature.…”

Section: Discussionmentioning

confidence: 99%

“…Note that the data on SrTi 0.9 Fe 0.1 O 3 and SrTi 0.9 Fe 0.1 O 2.95 calculated with the theoretical phase and amplitude were previously published. 17 In the first step, the experimental spectrum of powder reference compound LaFeO 3 was analyzed using the theoretically calculated scattering phase and amplitude. In the second step, all experimental spectra from powder references and the single crystal were treated with the experimental phase and amplitude extracted from the LaFeO 3 spectra, as well as with theoretical phase and amplitude.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic study of the electric field induced valence change of Fe-defect centers in SrTiO3

Lenser

Kalinko

Kuzmin

et al. 2011

Phys. Chem. Chem. Phys.

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The electrochemical changes induced by an electric field in Fe-doped SrTiO 3 have been investigated by X-ray absorption spectroscopy (XANES and EXAFS), electron paramagnetic resonance (EPR) and Raman spectroscopy. A detailed study of the Fe dopant in the regions around the anode and cathode reveals new insights into the local structure and valence state of Fe in SrTiO 3 single crystals. The ab initio full multiple-scattering XANES calculations give an evidence of the oxygen vacancy presence in the first coordination shell of iron. Differences in the length and disorder of the Fe-O bonds as extracted from EXAFS are correlated to the unequivocal identification of the defect type by complementary spectroscopical techniques to identify the valence state of the Fe-dopant and the presence of the Fe À V Ö complexes. Through this combinatorial approach, novel structural information on Fe À V Ö complexes is provided by X-ray absorption spectroscopy, and the relation of Fe-O bond length, doping level and oxidation state in SrTi 1Àx Fe x O 3 is briefly discussed.

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“…for cubic Sr(Mg 0.05 Ti 0.95 )O 3À where a weak new peak at 762 cm À1 was observed [19] and for orthorhombic Ca(Zr x Ti 1Àx )O 3 where a strong additional peak in the range of 750-800 cm À1 was found for 0.25 x 0.75 [20]. Spectra measured on oxygen vacancy containing Sr(Sc 0.03 Ti 0.97 )O 2.985 also do not show first-order Raman peaks [21]. For the SrTi 1Àx Fe x O 3 nanoparticles, a pronounced line at 700 cm À1 appears at an iron concentration as low as x ¼ 0.1.…”

Section: Resultsmentioning

confidence: 92%

SrTi_1−xFe_xO₃nanoparticle: a study of structural, optical, impedance and magnetic properties

Minh

Phuong

2011

Journal of Experimental Nanoscience

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We investigate the effects of Fe-dopant concentration on the structure, as well as optical, electrical transport and magnetic properties of SrTi 1Àx Fe x O 3 (x ¼ 0.00, 0.10, 0.20, 0.30, 0.40 and 0.50) nanoparticles prepared by sol-gel method. The dopant-induced changes are studied by X-ray diffraction (XRD), Raman, optical absorption, impedance and magnetic measurements. The results show an average particle size of about 15-30 nm, depending on the Fe-doped concentration. The decrease in lattice parameters and the change of phonon modes related to structural changes, decreasing gap with increasing dopant concentration in conjunction with increasing grain boundary contribution to the impedance. The Fe-doped content has affected the structure, absorption and Raman spectroscopy of the samples. These indicate that the Fe ion has replaced the site of Ti in unit cell. By this method, we have decreased the annealing temperature considerably than that in the conventional solid-state reaction.

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Jahn-Teller distortion aroundFe4+inSr(FexTi

Cited by 133 publications

References 60 publications

Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO₃

Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO₃

Spectroscopic study of the electric field induced valence change of Fe-defect centers in SrTiO3

SrTi_1−xFe_xO₃nanoparticle: a study of structural, optical, impedance and magnetic properties

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Jahn-Teller distortion aroundFe4+inSr(FexTi

Cited by 133 publications

References 60 publications

Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO3

Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO3

Spectroscopic study of the electric field induced valence change of Fe-defect centers in SrTiO3

SrTi1−xFexO3nanoparticle: a study of structural, optical, impedance and magnetic properties

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Product

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Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO₃

Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO₃

SrTi_1−xFe_xO₃nanoparticle: a study of structural, optical, impedance and magnetic properties