Static dielectric response and polar phonons of Ba(Mn1/3Nb2/3)O3 and Ba(Ni1/3Nb2/3)O3 complex perovskites

Dai, Jianhui; Zhang, Hu; Song, Yu-Min

doi:10.1016/j.commatsci.2013.07.044

Cited by 3 publications

(5 citation statements)

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“…Such a phenomenon is in accordance with the observation that the high-spin Mn 2+ -containing compounds, such as columbite MnNb 2 O 6 and complex perovskite Ba 3 MnNb 2 O 9 , possess higher conductivity and microwave dielectric loss compared with the Zn 2+ analogues, which may be explained using their electronic structures depending on the 3d electron configurations of the high-spin d 5 Mn 2+ and fully filled d 10 Zn 2+ . As for the electronic conduction over the extrinsic band gap, in the Mott insulator BMN (similar to the 3C ordered Ba 3 MnNb 2 O 9 ), the electrons mainly hop from VBM Mn 3d orbits to CBM Nb 4d orbits (Figure a–c) over a ∼2.0 eV gap. This is much smaller than that (∼3.9 eV) for the charge-transfer insulator BZN, where the electrons mainly hop from the VBM O 2p orbits to CBM Nb 4d orbits (Figure d–f).…”

Section: Discussionmentioning

confidence: 95%

“…The half-filled Mn 3d orbits in BMN could soften infrared modes, which increases the lattice vibration anharmonicity and therefore the intrinsic dielectric loss. 49 On the other hand, resonant spin excitation of unpaired transition-metal d electrons has been recently recognized as a noticeable origin of the microwave dielectric loss of transitionalmetal-doped complex perovskite Ba 3 ZnTa 2 O 9 resonators at cryogenic temperatures. 51 This mechanism could be also applicable here to BMN, which contains large amounts of unpaired d electrons in the high-spin Mn 2+ .…”

Section: ■ Discussionmentioning

confidence: 99%

“…Although the dielectric loss is generally highly sensitive to the processing which significantly impacts the extrinsic loss associated with the porosity, defects, cationic order, and secondary phase formation, , the large microwave dielectric loss of BMN could be mainly related to the existence of the high-spin d 5 Mn 2+ cations in BMN. The half-filled Mn 3d orbits in BMN could soften infrared modes, which increases the lattice vibration anharmonicity and therefore the intrinsic dielectric loss . On the other hand, resonant spin excitation of unpaired transition-metal d electrons has been recently recognized as a noticeable origin of the microwave dielectric loss of transitional-metal-doped complex perovskite Ba 3 ZnTa 2 O 9 resonators at cryogenic temperatures .…”

Section: Discussionmentioning

confidence: 99%

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8-Layer Shifted Hexagonal Perovskite Ba₈MnNb₆O₂₄: Long-Range Ordering of High-Spin d⁵ Mn²⁺ Layers and Electronic Structure

et al. 2018

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A new 8-layer shifted hexagonal perovskite BaMnNbO has been synthesized in air, featuring unusual long-range B-cation ordering with single octahedral high-spin d Mn layers separated by ∼1.9 nm within the corner-sharing octahedral d Nb host, analogous to Ba(Zn/Co)NbO. The large size and charge differences between high-spin Mn and Nb, as well as the out-of-center distortion of NbO octahedra associated with the bonding covalence and second-order Jahn-Teller effect of Nb, drive long-range cationic ordering, thus stabilizing BaMnNbO. The BaMnNbO pellet exhibits a high dielectric permittivity, ε ∼ 38, and a large temperature coefficient of resonant frequency, τ ∼ 20 ppm/K, but a dielectric loss ( Qf ∼ 987 GHz) and conductivity (∼10-10 S/cm within 473-1173 K) much higher than those of BaZnNbO. Electronic structures from density functional theory calculations reveal that BaMnNbO is a Mott insulator in contrast with the charge-transfer insulator nature of BaZnNbO, and they confirm that the off-center distortion of Nb contributes to stabilization of the 8-layer ordered shifted structure. The contrast between conductivity and dielectric loss of BaMnNbO and BaZnNbO is understood based on the electronic structure that depends on high-spin d Mn and d Zn cations. The hopping of 3d valence electrons in high-spin Mn to Nb 4d conduction bands over a small gap (∼2.0 eV) makes BaMnNbO more conductive than BaZnNbO, where the electrons are conducted via the hopping of a lattice O 2p valence electron to the Nb 4d conduction bands over a larger gap (∼3.9 eV). The high microwave dielectric loss of BMN may be mainly ascribed to the half-filled Mn 3d orbits, which is understood based on the softened infrared modes that increase the lattice vibration anharmonicity as well as the resonant spin excitation of unpaired d electrons.

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Section: Discussionmentioning

confidence: 95%

Section: ■ Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

8-Layer Shifted Hexagonal Perovskite Ba₈MnNb₆O₂₄: Long-Range Ordering of High-Spin d⁵ Mn²⁺ Layers and Electronic Structure

et al. 2018

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“…In general, the compounds containing transitional metal cations with partially filled 3 d shells have higher dielectric loss than the Mg 2+ /Zn 2+ analogues, implying an important role of 3 d electron number or d shell configuration on controlling the dielectric loss . Electronic structure calculation of Ba 3 MnNb 2 O 9 and Ba 3 NiNb 2 O 9 indicates that the half-filled t 2g orbitals in Mn 2+ and fully filled t 2g orbitals in Ni 2+ are responsible for the difference between their lattice vibration modes: the half-filled Mn t 2g orbitals soften infrared modes and increase lattice vibration inharmonicity and therefore the intrinsic loss . The 3 d electronic configuration of the high-spin d 5 Mn 2+ cations may also explain the origin of the high dielectric loss of the 14-layer twinned BMT material.…”

Section: Discussionmentioning

confidence: 99%

“…32 Electronic structure calculation of Ba 3 MnNb 2 O 9 and Ba 3 NiNb 2 O 9 indicates that the half-filled t 2g orbitals in Mn 2+ and fully filled t 2g orbitals in Ni 2+ are responsible for the difference between their lattice vibration modes: the half-filled Mn t 2g orbitals soften infrared modes and increase lattice vibration inharmonicity and therefore the intrinsic loss. 33 The 3d electronic configuration of the high-spin d 5 Mn 2+ cations may also explain the origin of the high dielectric loss of the 14-layer twinned BMT material. However, the dielectric loss is generally highly sensitive to the processing which significantly impacts the extrinsic loss associated with the porosity, cationic order, and secondary phase formation.…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

First 14-Layer Twinned Hexagonal Perovskite Ba₁₄Mn_1.75Ta_10.5O₄₂: Atomic-Scale Imaging of Cation Ordering

Tao

Genevois

et al. 2016

Chem. Mater.

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Formation of hexagonal perovskite with mixed cubic and hexagonal stacking of AO 3 layers becomes more and more difficult when the number of layers in the stacking repeating unit increases. So far, the highest number of layers reported for twinned hexagonal perovskite is 12, with alternative 5 consecutive cubic layers and one hexagonal layer in the (ccccch) 2 sequence. Here, we present the unexpected formation of a 14-layer twinned hexagonal perovskite with a stacking sequence (cccccch) 2 for the BaO 3 layers on the Ba 14 Mn 1.75 Ta 10.5 O 42 (Ba 8 MnTa 6 O 24 ) composition, the first example of twinned hexagonal perovskite with a periodicity exceeding 12-layers. The B-cation and vacancy distributions are characterized by multiple efficient and complementary techniques including neutron and synchrotron powder diffraction, scanning transmission electron microscopyhigh angle annular dark field (STEM-HAADF) imaging, and electron energy loss spectroscopy (EELS) and X-ray energy dispersive spectroscopy (EDS) elemental mapping. Atomic-resolution STEM-HAADF imaging and EELS/EDS elemental mapping enables direct observation of high-spin d 5 Mn 2+ cation ordering in the d 0 Ta 5+ host, thus demonstrating the great potential of this technique for probing cation ordering and performing structure determination. Moreover, atomic mapping allows for the observation of local defect structure variants, which can be a powerful tool for future new material design. The large high-spin Mn 2+ cation and Ta-vacancy pair formation in face-sharing octahedral sites play key roles on both the stabilization of this 14-layer twinned hexagonal perovskite structure and the Mn 2+ ordering in the central corner-sharing octahedral (CSO) positions within the five-consecutive CSO layers. Compared with the 8-layer twinned Ba 8 ZnTa 6 O 24 material, the low quality factor in microwave frequency and enhanced ultraviolet and visible light absorption of Ba 14 Mn 1.75 Ta 10.5 O 42 as well as the photocatalytic activity on water splitting are discussed in terms of the presence of high-spin Mn 2+ cations in the structure. ■ INTRODUCTIONMetal oxide materials based on the ABO 3 perovskite family are of great importance in current solid state chemistry and physics given their structural diversity and their technologically relevant physical properties, 1,2 e.g., superconductivity, 2,3 ferromagnetism, 2 ionic motion, 4,5 low dielectric loss, 6,7 etc. The cubic ABO 3 perovskite structure is built up from cubic-close-packed AO 3 layers with B cations occupying the octahedral sites between the AO 3 layers. Similarly, hexagonal perovskite oxides contain the same building units of close-packed AO 3 layers but arranged with hexagonal or mixed cubic-hexagonal close packing. These structures are interesting prototypes to be exploited for structural chemistry and physical properties in order to provide a deeper understanding of the fundamental chemistry and physics of materials in the cubic perovskite family and possibly to further discover potential new materials.The mos...

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Electronic structure, lattice dynamics, and dielectric properties in cubic perovskite BiMn3Cr4O12 and LaMn3Cr4O12

Dai

Liang

2020

Chemical Physics

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Static dielectric response and polar phonons of Ba(Mn1/3Nb2/3)O3 and Ba(Ni1/3Nb2/3)O3 complex perovskites

Cited by 3 publications

References 56 publications

8-Layer Shifted Hexagonal Perovskite Ba₈MnNb₆O₂₄: Long-Range Ordering of High-Spin d⁵ Mn²⁺ Layers and Electronic Structure

8-Layer Shifted Hexagonal Perovskite Ba₈MnNb₆O₂₄: Long-Range Ordering of High-Spin d⁵ Mn²⁺ Layers and Electronic Structure

First 14-Layer Twinned Hexagonal Perovskite Ba₁₄Mn_1.75Ta_10.5O₄₂: Atomic-Scale Imaging of Cation Ordering

Electronic structure, lattice dynamics, and dielectric properties in cubic perovskite BiMn3Cr4O12 and LaMn3Cr4O12

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Static dielectric response and polar phonons of Ba(Mn1/3Nb2/3)O3 and Ba(Ni1/3Nb2/3)O3 complex perovskites

Cited by 3 publications

References 56 publications

8-Layer Shifted Hexagonal Perovskite Ba8MnNb6O24: Long-Range Ordering of High-Spin d5 Mn2+ Layers and Electronic Structure

8-Layer Shifted Hexagonal Perovskite Ba8MnNb6O24: Long-Range Ordering of High-Spin d5 Mn2+ Layers and Electronic Structure

First 14-Layer Twinned Hexagonal Perovskite Ba14Mn1.75Ta10.5O42: Atomic-Scale Imaging of Cation Ordering

Electronic structure, lattice dynamics, and dielectric properties in cubic perovskite BiMn3Cr4O12 and LaMn3Cr4O12

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8-Layer Shifted Hexagonal Perovskite Ba₈MnNb₆O₂₄: Long-Range Ordering of High-Spin d⁵ Mn²⁺ Layers and Electronic Structure

8-Layer Shifted Hexagonal Perovskite Ba₈MnNb₆O₂₄: Long-Range Ordering of High-Spin d⁵ Mn²⁺ Layers and Electronic Structure

First 14-Layer Twinned Hexagonal Perovskite Ba₁₄Mn_1.75Ta_10.5O₄₂: Atomic-Scale Imaging of Cation Ordering