Conductive electrique caracterisation cristallographique des composes de type perovskite NdCu3RuxTi4−xO12(1 &lt; x &lt; 4) etNd(2+x)/3Cu3RuxTi4−xO12 (x &lt; 1)

Müller, J.; Haouzi, A.; Laviron, C.; Labeau, M.; Joubert, J.C.

doi:10.1016/0025-5408(86)90230-8

Cited by 13 publications

(11 citation statements)

References 13 publications

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“…As can be seen, exactly the same behavior as described for the EXAFS-distances (Fig. 5) (10). Finally, our cell parameters are in accordance with the values previously given by Labeau et al (17).…”

Section: Xrd-rietveldsupporting

confidence: 84%

“…By comparing the amplitudes and phases of both paths we found that the direct scattering is by far the more important process. This is in contrast to the system La 2Àx Sr x Cu 1Ày Ru y O 4Àd in which the multiple scattering was found to dominate (5 (10). It is well known that multiple scattering paths play an important role for co-linear arrangements while their amplitude decreases dramatically with a decrease of the angle (11).…”

Section: Ru-k Exafscontrasting

confidence: 53%

“…As the starting structural model, the refined cell parameters derived from the XRD measurements (see below) and the fractional atomic coordinates given by Muller et al for NdCu 3 Ru 4 O 12 (10) were used. The relevance of the different scattering paths was then checked by calculating their contribution to the mRDF.…”

Section: Ru-k Exafsmentioning

confidence: 99%

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Structural Investigations of ACu3Ru4O12 (A=Na, Ca, Sr, La, Nd)—A Comparison between XRD-Rietveld and EXAFS Results

Ebbinghaus

Weidenkaff

Cava

2002

Journal of Solid State Chemistry

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Section: Xrd-rietveldsupporting

confidence: 84%

Section: Ru-k Exafscontrasting

confidence: 53%

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Structural Investigations of ACu3Ru4O12 (A=Na, Ca, Sr, La, Nd)—A Comparison between XRD-Rietveld and EXAFS Results

Ebbinghaus

Weidenkaff

Cava

2002

Journal of Solid State Chemistry

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“…The cell-parameter values for the Nd series are in very good agreement with data reported by Muller et al in ref. 24. Details of the structural data such as refinement parameters, bond lengths and angles as well as the measured XRD patterns are given in the ESI.…”

Section: Crystal Structure and Oxygen Stoichiometrymentioning

confidence: 99%

Valence properties of Cu and Ru in titanium-substituted LnCu₃Ru₄O_12+δ (Ln = La, Pr, Nd) investigated by XANES and TGA

et al. 2015

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In the solid-solution series La(y)Cu(3)RuxTi(4-x)O(12+δ) (0 ≤x≤ 4) the Cu and Ru electronic states are highly correlated. With increasing Ru content x the system properties change from a paramagnetic insulator with colossal dielectric constant to a heavy-fermion metal. To further elucidate the occurring phase transitions, the valences of Cu and Ru have been investigated utilizing XANES measurements at the Cu-K and the Ru-K absorption edges. It was found that the Ru oxidation number is close to +4 in all samples, while the Cu valence linearly decreases from +2 for the titanate (x = 0) to +1.6 for the ruthenate (x = 4). Additional thermogravimetric measurements have been used to determine the oxygen content and rather high oxygen excesses up to δ≈ 0.7 (for x = 0.5) were obtained. The additional oxygen for x < 2 is required to compensate the constant Ru +4 valence. Our findings are in accordance with the reported phase transitions of the magnetic and transport properties. Both the valence shift and the shapes of the absorption edges suggest a change from localized to itinerant character of the Cu electronic states with increasing x, while the Ru electrons remain localized. Analogous results concerning the valences were found for the Pr(y)Cu(3)RuxTi(4-x)O(12+δ) and Nd(y)Cu(3)RuxTi(4-x)O(12+δ) solid-solution series.

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“…Examples of the second type of A-cation ordering, those arising from differences in the coordination preferences of A and A', belong almost exclusively to a family of compounds with stoichiometry A'A 3 M 4 O 12 (A = Cu 2+ , Mn 2+ ; A' = Na, Ca, Y, Nd, La, Th; M = Mn, Ti, Ge, Ru). Members of this family include NaCu 3 Mn 4 O 12 , CaCu 3 Ti 4 O 12 , CaCu 3 Ge 4 O 12 , NdCu 3 Ru 4 O 12 , and the parent compound of this structure type, NaMn 3 Mn 4 O 12 a + a + a + . − The distortion of the oxygen network in this tilt system is such that 25% of the A-site cations have a distorted cubooctahedral coordination with 12 equidistant oxygen neighbors, whereas the remaining 75% have square-planar coordination, as shown in Table .…”

Section: Cation Orderingmentioning

confidence: 99%

Predictive Modeling and High-Pressure−High-Temperature Synthesis of Perovskites Containing Monovalent Silver

1998

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The program POTATO, which was developed to model distorted perovskite structures, has been used to assess the stability of hypothetical compositions and guide the synthesis of new materials at high pressures and high temperatures. The initial result of this effort is the synthesis of two new perovskites, Ca2NdAgTi4O12 and NdAgTi2O6, which were synthesized at 14−14.5 GPa and 1000 °C using the uniaxial split sphere anvil type press (USSA-2000). Both compounds are perovskites distorted from the ideal cubic structure by octahedral tilting distortions. Ca2NdAgTi4O12 contains a random distribution of Ca2+/Nd3+/Ag+ ions on the A-site, whereas NdAgTi2O6 has a partially ordered distribution of Nd3+/Ag+ ions. Ca2NdAgTi4O12 adopts the GdFeO3 structure (Glazer tilt system b-a+b-), space group Pnma, with a = 5.44883(4), b = 7.68915(6), and c = 5.42290(3) Å. NdAgTi2O6 belongs to the tetragonal space group P4/nbm, with a = 5.45337(3) and c = 7.72934(6) Å. This structure can be derived from the simple cubic perovskite structure by rotations of the octahedra about the c-axis (Glazer tilt system a0a0c-) and partial ordering of Nd3+ and Ag+ ions into alternating layers, perpendicular to the c-axis.

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Conductive electrique caracterisation cristallographique des composes de type perovskite NdCu3RuxTi4−xO12(1 < x < 4) etNd(2+x)/3Cu3RuxTi4−xO12 (x < 1)

Cited by 13 publications

References 13 publications

Structural Investigations of ACu3Ru4O12 (A=Na, Ca, Sr, La, Nd)—A Comparison between XRD-Rietveld and EXAFS Results

Structural Investigations of ACu3Ru4O12 (A=Na, Ca, Sr, La, Nd)—A Comparison between XRD-Rietveld and EXAFS Results

Valence properties of Cu and Ru in titanium-substituted LnCu₃Ru₄O_12+δ (Ln = La, Pr, Nd) investigated by XANES and TGA

Predictive Modeling and High-Pressure−High-Temperature Synthesis of Perovskites Containing Monovalent Silver

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Conductive electrique caracterisation cristallographique des composes de type perovskite NdCu3RuxTi4−xO12(1 < x < 4) etNd(2+x)/3Cu3RuxTi4−xO12 (x < 1)

Cited by 13 publications

References 13 publications

Structural Investigations of ACu3Ru4O12 (A=Na, Ca, Sr, La, Nd)—A Comparison between XRD-Rietveld and EXAFS Results

Structural Investigations of ACu3Ru4O12 (A=Na, Ca, Sr, La, Nd)—A Comparison between XRD-Rietveld and EXAFS Results

Valence properties of Cu and Ru in titanium-substituted LnCu3Ru4O12+δ (Ln = La, Pr, Nd) investigated by XANES and TGA

Predictive Modeling and High-Pressure−High-Temperature Synthesis of Perovskites Containing Monovalent Silver

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Valence properties of Cu and Ru in titanium-substituted LnCu₃Ru₄O_12+δ (Ln = La, Pr, Nd) investigated by XANES and TGA