EPR spectra and local lattice structure of Fe3+ impurity ions in ferroelectric LiNbO3

Wang, Hui; Kuang, Xiao‐Yu; Die, Dong; Tan, Xiaoming; Xiong, Yong

doi:10.1016/j.chemphys.2006.08.013

Cited by 14 publications

(4 citation statements)

References 27 publications

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“…We assume that the majority of the Fe ions in the compound are trivalent due to the oxidizing conditions in the air during all the preparing process. This has been confirmed by electron paramagnetic resonance on Fe‐doped KTN, 24,25,30 however, the sites where Fe 3+ ions occupy is not very clear 25–28,31,32 . Regarding this matter, E. Possenriede et al 30 concluded that Fe 3+ (0.064 nm) ions in KTN system occupy Nb 5+ (0.069 nm) and Ta 5+ (0.068 nm) sites.…”

Section: Resultsmentioning

confidence: 92%

Structure and Piezoelectric Properties of Fe-Doped Potassium Sodium Niobate Tantalate Lead-Free Ceramics

Yang

Zhou

Yang

et al. 2011

Journal of the American Ceramic Society

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Lead‐free (1−x/2) K0.5Na0.5Nb0.95Ta0.05O3–x/2Fe2O3 piezoelectric ceramics (x=0, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0, and 3.0 mol%) have been prepared by conventional ceramic sintering process. The effects of doped iron element on the structure, dielectric, and piezoelectric properties were investigated. The introduction of ferric oxide (Fe2O3) was effective in improving the piezoelectric properties and sintering characteristics by refining grain size, reducing micropores and increasing the density of the ceramics. The bulk density reached the steady value of around 4.52 g/cm3, about 96% of the theoretical value. The samples with x=0.4 mol% show the maximum values of the piezoelectric coefficient (d33=130 pC/N) and the planar electromechanical coupling coefficient (kP=37.2%), which is significantly enhanced compared with the undoped samples. K+ and Na+ vacancies and charge compensation of the diffused Fe ions in the ceramics induce domain wall motions, which might be responsible for the improvement of structure and electrical properties. Fe2O3 was considered to be a “soft” addition for alkali niobate piezoelectric ceramics at low doping concentration.

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Section: Resultsmentioning

confidence: 92%

Structure and Piezoelectric Properties of Fe-Doped Potassium Sodium Niobate Tantalate Lead-Free Ceramics

Yang

Zhou

Yang

et al. 2011

Journal of the American Ceramic Society

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“…The above properties can be investigated by means of electron paramagnetic resonance (EPR) [13][14][15][16]. For example, EPR studies were carried out on Co 2+ doped LiNbO 3 and LiTaO 3 , and the spin Hamiltonian parameters (g factors g // , g ⊥ and the hyperfine structure constants A // and A ⊥ ) for the trigonal Co 2+ centers were also measured [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigations of the local structures and spin Hamiltonian parameters for the trigonal Co2+ centers in LiNbO3 and LiTaO3

Wei

et al. 2009

Journal of Alloys and Compounds

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“…EPR studies have shown that the dominant iron center, Fe 1 in cLN has axial symmetry with the ZFS b 0 2 about 0.1680 cm −1 [131,133,134,[198][199][200][201][202][203][204][205][206][207][208]. Calculations of optical and EPR characteristics based on the superposition models or generalized crystal field theory gave a preference for Nb substitution [209], no definite conclusion for Li or Nb substitution [210][211][212][213] or some preference for Li site [214,215]. Mössbauer [33,34] and Raman [35] spectroscopy data, Stark effect [216] were interpreted on the base of Fe substitution for Li.…”

Section: Trivalent Cationsmentioning

confidence: 99%

Structures of Impurity Defects in Lithium Niobate and Tantalate Derived from Electron Paramagnetic and Electron Nuclear Double Resonance Data

Грачев

Malovichko

2021

Crystals

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Point intrinsic and extrinsic defects, especially paramagnetic ions of transition metals and rare-earth elements, have essential influence on properties of lithium niobate, LN and tantalate, LT, and often determine their suitability for numerous applications. Discussions about structures of the defects in LN/LT have lasted for decades. Many experimental methods facilitate progress in determining the structures of impurity centers. This paper gives current bird’s eye view on contributions of Electron Paramagnetic Resonance (EPR), and Electron Nuclear Double Resonance (ENDOR) studies to the determination of impurity defect structures in LN and LT crystals for a broad audience of researchers and students. Symmetry and charge compensation considerations restrict a number of possible structures. Comparison of measured angular dependences of ENDOR frequencies with calculated ones for Li and Nb substitution using dipole–dipole approximation allows unambiguously to determine the exact location of paramagnetic impurities. Models with two lithium vacancies explain angular dependencies of EPR spectra for Me3+ ions substituting for Li+ like Cr, Er, Fe, Gd, Nd, and Yb. Self-compensation of excessive charges through equalization of concentrations of Me3+(Li+) and Me3+(Nb5+) and appearance of interstitial Li+ in the structural vacancy near Me3+(Nb5+) take place in stoichiometric LN/LT due to lack of intrinsic defects.

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EPR spectra and local lattice structure of Fe3+ impurity ions in ferroelectric LiNbO3

Cited by 14 publications

References 27 publications

Structure and Piezoelectric Properties of Fe-Doped Potassium Sodium Niobate Tantalate Lead-Free Ceramics

Structure and Piezoelectric Properties of Fe-Doped Potassium Sodium Niobate Tantalate Lead-Free Ceramics

Theoretical investigations of the local structures and spin Hamiltonian parameters for the trigonal Co2+ centers in LiNbO3 and LiTaO3

Structures of Impurity Defects in Lithium Niobate and Tantalate Derived from Electron Paramagnetic and Electron Nuclear Double Resonance Data

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