Improper ferroelectricity in helicoidal antiferromagnet Cu3Nb2O8

Sharma, Gyaneshwar; Saha, J.; Kaushik, S. D.; Siruguri, V.; Patnaik, S.

doi:10.1016/j.ssc.2014.11.016

Cited by 9 publications

(7 citation statements)

References 28 publications

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“…41,42 Besides, these vibrations are located in a similar position to those of the Cu 3 Nb 2 O 8 phase, as found earlier. 31,32 For ZnNb, two sets of vibrations constituting 23 Raman modes are detected, all of them in agreement with literature reports on the orthorhombic zinc niobate ZnNb 2 O 6 (D 14 2h ) crystal structures reported. 33,43 Moreover, Raman bands of the Zn 3 Nb 2 O 8 phase are located in positions close to that of ZnNb 2 O 6 , 35,36 which corroborates with the XRD results.…”

Section: Papersupporting

confidence: 90%

“…In addition, the parameters including unit cells, lattice constants and angles are found to be consistent with the parameters reported earlier. 32,34 Interestingly, the XRD peaks match with those of the monoclinic Zn 3 Nb 2 O 8 pyrochlore structure (ICSD 36290, space group C2/c). This may be due to the combined effects of the amounts of the ZnO and Nb 2 O 5 precursors used during the preparation of the sample and the calcination temperature leading to the mixture of Zn 3 Nb 2 O 8 and ZnNb 2 O 6 , in agreement with the findings.…”

Section: Structural Features By Xrdmentioning

confidence: 71%

“…This result is also corroborated by the Rietveld refinement, which suggested the presence of the aforesaid phase, and is in good agreement with the findings. 31,32 The diffraction peaks representing the orthorhombic ZnNb 2 O 6 pyrochlore phase (ICSD 36290) for ZnNb is found. Besides, the columbite-type orthorhombic structure belongs to the space group Pbcn and possesses lattice constants a = 14.208 Å, b = 5.726 Å, and c = 5.04 Å and lattice angles α = β = γ = 90°, in line with the findings.…”

Section: Structural Features By Xrdmentioning

confidence: 98%

See 2 more Smart Citations

Metal-doped niobate pyrochlores and double-perovskites for glycerol valorization: structural and electronic properties and DFT calculations

Bertoldo,

Oliveira,

Saraiva

et al. 2024

Dalton Trans.

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Section: Papersupporting

confidence: 90%

Section: Structural Features By Xrdmentioning

confidence: 71%

Section: Structural Features By Xrdmentioning

confidence: 98%

See 1 more Smart Citation

Metal-doped niobate pyrochlores and double-perovskites for glycerol valorization: structural and electronic properties and DFT calculations

Bertoldo,

Oliveira,

Saraiva

et al. 2024

Dalton Trans.

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“…Generally, the crystal structure of copper niobate consists of edge sharing metal‐oxygen octahedra and the diffraction does not show the difference in the stacking of the layers of copper and niobium with oxygen to form a honeycomb layers. The d‐spacing value between the spots corresponds to the plane (100), (001) and

((), 1 \overset{1}{true} 0)

and its inverse plane confirming the formation of triclinic phase of Cu 3 Nb 2 O 8 32 . No other crystal structure of the precursors (CuO/Nb 2 O 5 ) or the intermediate compound was detected.…”

Section: Resultsmentioning

confidence: 71%

Fabrication of copper‐niobium‐oxygen complexes as a photocathode for p‐type dye‐sensitized solar cell

et al. 2021

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Summary Thin film of copper niobate ternary oxide with various compositions was fabricated by pulsed laser deposition technique. Formation of a single phase of monoclinic CuNbO3, monoclinic CuNb3O8 (Cu[I]), and triclinic Cu3Nb2O8 (Cu[II]) thin films was confirmed from the X‐ray diffraction and selected area energy diffraction analysis. Field emission scanning electron microscopy and high‐resolution tunneling electron microscope show CuNbO3 and CuNb3O8 system that exhibits polyhedron and triangular structure, respectively, while Cu3Nb2O8 system shows layered structure formation. The linear spectrum shows a minimal variation in bandgap concerning to the change in elemental composition and position of the copper and niobium atom. Cyclic voltammetry studies endorse that the prepared films are highly adhesive even after 100 cycles. With various compositions of copper niobate thin films as photocathode, N719 sensitized p‐dye‐sensitized solar cells (p‐DSSCs) were fabricated for the first time. Monoclinic CuNbO3 system offers outstanding photovoltaic performance of 2.19% and thus can be used as an alternative for well‐known NiO p‐DSSC. Advantages of copper‐niobium‐oxygen systems open a new route of photocathodic materials for p‐DSSC and tandem solar cells.

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“…This model was supported by Sharma et al [19] However, Xiang et al proposed a more general model of helical multiferroics [20] in which a polarization is induced purely through the presence of a noncollinear magnetic structure. The polarization results from noncollinear spin dimers (the exchange pairs) and is expanded as a power series and the coefficients determined by first-principles density functional theory (DFT) calculations.…”

Section: Introductionmentioning

confidence: 89%

Imitation of spin density wave order in Cu3Nb2O8

et al. 2020

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Spin density waves, based on modulated local moments, are usually associated with metallic materials, but have recently been reported in insulators which display coupled magnetic and structural order parameters. We discuss one such example, the multiferroic Cu 3 Nb 2 O 8 , which is reported to undergo two magnetic phase transitions, first to an unknown antiferromagnetic phase at T N ≈ 26.5 K, and then to a helicoidal structure coupled to an electric polarization below T 2 ≈ 24 K [R. D. Johnson et al., Phys. Rev. Lett. 107, 137205 (2011)] which breaks the crystallographic inversion symmetry. By analogy with other complex oxides, one might naturally expect this intermediate phase to be a spin density wave phase. We apply spherical polarimetry to confirm the low-temperature magnetic structure, yet only observe a single magnetic phase transition to helicoidal order. We argue that the reported unknown phase actually supports an imitation spin density wave which originates from a decoupling of the components of the magnetic order parameter, as allowed by symmetry and driven by thermal fluctuations. This provides a mechanism for the magnetic, but not nuclear, structure to break inversion symmetry thereby creating an intermediate phase in the proximity of T N which imitates a spin density wave. As the temperature is reduced, this intermediate structure destabilizes the crystal such that a structural chirality is induced, as reflected by the emergence of the electric polarization, and the imitation spin density wave relaxes into a generic helicoid. This scenario in which critical fluctuations allow the magnetic structure to break inversion symmetry while the crystal structure remains centrosymmetric might be relevant to other complex multiferroics.

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Improper ferroelectricity in helicoidal antiferromagnet Cu3Nb2O8

Cited by 9 publications

References 28 publications

Metal-doped niobate pyrochlores and double-perovskites for glycerol valorization: structural and electronic properties and DFT calculations

Metal-doped niobate pyrochlores and double-perovskites for glycerol valorization: structural and electronic properties and DFT calculations

Fabrication of copper‐niobium‐oxygen complexes as a photocathode for p‐type dye‐sensitized solar cell

Imitation of spin density wave order in Cu3Nb2O8

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