Structural, vibrational and optical properties of Eu3+-doped Gd3NbO7 niobates – The mechanism of their structural phase transition

Ptak, Maciej; Pilarek, Bożena; Watras, Adam; Godlewska, P.; Szczygieł, I.; Hanuza, J.

doi:10.1016/j.jallcom.2019.151892

Cited by 12 publications

(15 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 2 shows the features of weberites RE 3 NbO 7 crystal structures with Cmcm, Pnma, and C222 1 SG ; three‐type polyhedrons are formed in these lattices. The weberites RE 3 NbO 7 can be viewed as layer‐like structures, based on the distorted [NbO 6 ], [REO 7 ] and [REO 8 ] polyhedrons 29,30 . The [NbO 6 ] and [REO 8 ] polyhedrons locate in the same layer, when [REO 7 ] polyhedrons locate between two [NbO 6 ]/[REO 8 ] layers.…”

Section: Results and Analysismentioning

confidence: 99%

Features of crystal structures and thermo‐mechanical properties of weberites RE₃NbO₇(RE=La, Nd, Sm, Eu, Gd) ceramics

et al. 2020

View full text Add to dashboard Cite

Abundant oxides are studied to replace present thermal barrier coatings (TBCs), yttria-stabilized zirconia (YSZ), to perfect the application performances. 1-8 YSZ displays relatively high thermal conductivity (2.5 W•m −1 •K −1 , 1000°C), high Young's modulus (~230 GPa), low application temperature (≤1200°C), and weak CaO-MgO-Al 2 O 3-SiO 2 corrosion resistance. 1,2,9-12 To conquer the weaknesses, multifarious means are applied to perfect YSZ properties, and diverse oxides are researched as novel TBCs. 3,6,13-20 RE 3 NbO 7 oxides (RE is rare earth) are considered as structural materials, as that they display low thermal conductivity (1.0-2.0 W•m −1 •K −1 , 25-900°C), high thermal expansion coefficients (11 × 10 −6 K −1 , 1200°C), and exceptional corrosion resistance. 16,21 The thermal transport mechanism and mechanical properties of fluorites RE 3 NbO 7 are well documented, and the thermal properties of weberites RE 3 NbO 7 are reported. 16,21,22 Besides thermal properties, hardness, toughness, and modulus are vital, nevertheless, the dominant mechanisms of mechanical properties of weberites RE 3 NbO 7 are not clear. The critical factors of hardness, toughness and modulus of ceramics include lattice distortion degree, bond length, microstructure features, and others. Suitable hardness, toughness, and modulus are demanded, and their mutual relations are connective. 23-26 To obtain TBCs with excellent working performance, the mechanical properties and corresponding dominant mechanisms are of great importance. The correlations among crystal structures, surface appearances and mechanical properties of weberites RE 3 NbO 7 are researched. The influences of bond length, lattice distortion degree, crystal structures and microstructures on mechanical properties are studied. Furthermore, the correlations between thermal and mechanical properties are connected. The dominant

show abstract

Section: Results and Analysismentioning

confidence: 99%

Features of crystal structures and thermo‐mechanical properties of weberites RE₃NbO₇(RE=La, Nd, Sm, Eu, Gd) ceramics

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Second, 24 IRactive transverse phonon modes can be resolved and noted in table 2. In analogy to the related compound Gd 3 NbO 7 [33] the modes above ∼190 cm −1 can be ascribed to stretching and and Ir 5+ ions.…”

Section: Optical Conductivitymentioning

confidence: 94%

“…Second, 24 IR-active transverse phonon modes can be resolved and noted in Table 2. In analogy to the related compound Gd 3 NbO 7 [33] the modes above ∼190 cm −1 can be ascribed to stretching and bending vibrations of IrO 6 octahedra, and the modes below ∼190 cm −1 can be assigned to translational modes of the Pr 3+ and Ir 5+ ions.…”

Section: Optical Conductivitymentioning

confidence: 97%

Fluorite-related iridate Pr₃IrO₇: crystal growth, structure, magnetism, thermodynamic, and optical properties

Kumar¹,

Köpf²,

A.³

et al. 2022

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Spin-orbit coupling in heavy 5$d$ metal oxides, in particular, iridates have received tremendous interest in recent years due to the realization of exotic electronic and magnetic phases. Here, we report the synthesis, structural, magnetic, thermodynamic, and optical properties of the ternary iridate Pr$_3$IrO$_7$. Single crystals of Pr$_3$IrO$_7$ have been grown by the KF flux method. Structural analysis shows that Pr$_3$IrO$_7$ crystallizes in an orthorhombic phase with $Cmcm$ symmetry. The electron energy loss spectroscopy study indicates that Pr is in a 3+ valence state, which implies a 5+ oxidation state of Ir. Magnetization data measured at high and low magnetic fields do not exhibit any bifurcation between $M_{ZFC}$ and $M_{FC}$, however, a weak hump in $M(T)$ is observed at $T^*$$\sim$10.4~K. The specific heat data reveal two maxima at $\sim$253 K and $\sim$4.8 K. The optical conductivity $\sigma_1(\omega)$ spectrum shows 26 infrared-active phonon modes and reveals an insulating behavior with an optical gap $\Delta_{OP}$ of size $\sim$500~meV. During cooling down, the temperature-dependent reflectivity spectrum reveals seven extra phonon modes below the structural phase transition ($\sim$ 253 K). An anomaly is observed at around $T^*$ in the temperature evolution of infrared-active mode frequencies suggesting the presence of significant spin-phonon coupling in the system.

show abstract

“…The study of niobium-based oxides, such as pyrochlores, perovskites, and columbites, has led to numerous applications in energy storage, , photocatalysis, , piezoelectricity, − optics, and magnetism . One important member of this family is Calcium Niobate – CaNb 2 O 6 .…”

Section: Introductionmentioning

confidence: 99%

“…The study of niobium-based oxides, such as pyrochlores, perovskites, and columbites, has led to numerous applications in energy storage, 1,2 photocatalysis, 3,4 piezoelectricity, 5−7 optics, 1 and magnetism. 8 One important member of this family is Calcium Niobate − CaNb 2 O 6 . 9 Among all structure types, orthorhombic columbite with a space group of Pbcn 10 is a well-known semiconductor with interesting luminescence properties, which is the key to optical applications.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis of CaNb₂O₆ with a Rynersonite-like Structure: Morphology, Rietveld Refinement, Optical, and Vibrational Properties

Nascimento,

Nobre,

Batista

et al. 2023

Inorg. Chem.

View full text Add to dashboard Cite

Structural, vibrational and optical properties of Eu3+-doped Gd3NbO7 niobates – The mechanism of their structural phase transition

Cited by 12 publications

References 49 publications

Features of crystal structures and thermo‐mechanical properties of weberites RE₃NbO₇(RE=La, Nd, Sm, Eu, Gd) ceramics

Features of crystal structures and thermo‐mechanical properties of weberites RE₃NbO₇(RE=La, Nd, Sm, Eu, Gd) ceramics

Fluorite-related iridate Pr₃IrO₇: crystal growth, structure, magnetism, thermodynamic, and optical properties

Synthesis of CaNb₂O₆ with a Rynersonite-like Structure: Morphology, Rietveld Refinement, Optical, and Vibrational Properties

Contact Info

Product

Resources

About

Structural, vibrational and optical properties of Eu3+-doped Gd3NbO7 niobates – The mechanism of their structural phase transition

Cited by 12 publications

References 49 publications

Features of crystal structures and thermo‐mechanical properties of weberites RE3NbO7(RE=La, Nd, Sm, Eu, Gd) ceramics

Features of crystal structures and thermo‐mechanical properties of weberites RE3NbO7(RE=La, Nd, Sm, Eu, Gd) ceramics

Fluorite-related iridate Pr3IrO7: crystal growth, structure, magnetism, thermodynamic, and optical properties

Synthesis of CaNb2O6 with a Rynersonite-like Structure: Morphology, Rietveld Refinement, Optical, and Vibrational Properties

Contact Info

Product

Resources

About

Features of crystal structures and thermo‐mechanical properties of weberites RE₃NbO₇(RE=La, Nd, Sm, Eu, Gd) ceramics

Features of crystal structures and thermo‐mechanical properties of weberites RE₃NbO₇(RE=La, Nd, Sm, Eu, Gd) ceramics

Fluorite-related iridate Pr₃IrO₇: crystal growth, structure, magnetism, thermodynamic, and optical properties

Synthesis of CaNb₂O₆ with a Rynersonite-like Structure: Morphology, Rietveld Refinement, Optical, and Vibrational Properties