Dielectric permittivity and electric modulus in Bi2Ti4O11

Li, Jianjun; Duan, Chun‐Gang; Yin, Wei‐Guo; Mei, W.; Smith, Robert W.; Hardy, J. R.

doi:10.1063/1.1587685

Cited by 263 publications

(67 citation statements)

References 22 publications

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“…At low temperature, there is a drastically decrease with frequency due to the change of ions moving from long distance to short distance at high frequency, where the ions will be confined into their ion potential wells and can occur only in a local motion (high frequency) [61,74]. In the temperature range of 200-300 K, the observed shoulder appears to be shifting towards high frequency side when the temperature increases.…”

Section: Vogel-fulcher Relationshipmentioning

confidence: 83%

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

2018

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Polycrystalline powders of (1-x)Na 0.5 Bi 0.5 TiO 3 -xCaTiO 3 ((1-x)NBT-xCT, 0 ≤ x ≤ 0.55) have been synthesized by solid state route. The effects of simultaneous substitution of Na + /Bi 3+ at A-site in NBT on structural and dielectric properties were investigated. X-ray diffraction analysis revealed the phase transition from rhombohedral structure (x = 0) to orthorhombic structure (x ≥ 0.15). A distinct behaviour in dielectric properties was obtained, where for x = 0, a normal ferroelectric behaviour was observed, whereas for x ≥ 0.15, a broad dielectric anomaly was revealed such that the maximum temperature (T m ) strongly depended on the frequency and shifted towards low temperature with CT. The dielectric dispersion indicated a relaxor behaviour revealed by the degree of diffuseness and modelled via Vogel-Fulcher relation. The study highlighted the relaxor behaviour as a function of frequency and proved the transformation from a relaxor high-frequency dependence to a paraelectric phase at temperature T s . The distinct variation of the Raman spectra at room temperature was correlated with X-ray diffraction results and proved the already mentioned transition. On heating (193-500 ℃), the Raman spectra confirmed the structural stability (Pnma) of the materials. The phonon behaviour for x = 0.15 was discussed in terms of the appearance of polar nanoregions (PNRs) into a non-polar orthorhombic matrix responsible of the relaxor behaviour. For x = 0.20, unchanged phonon behaviour confirmed the variation in dielectric behaviour where the solids transformed from a relaxor to a paraelectric state without structural phase transition.

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Section: Vogel-fulcher Relationshipmentioning

confidence: 83%

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

2018

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“…In general, electric modulus corresponds to the relaxation of the electric field in the material when the electric displacement remains constant. The effectiveness of the modulus illustration in the analysis of the relaxation properties has been demonstrated for many polycrystalline ceramics [27][28][29]. Figure 6 shows the frequency dependence of M  at various SM T .…”

Section: Electric Modulus Analysismentioning

confidence: 99%

Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

2015

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Abstract:The electrical properties of Ni 0.27 Cu 0.10 Zn 0.63 Fe 2 O 4 (NCZF) prepared from auto combustion synthesis of ferrite powders have been studied by impedance and modulus spectroscopy. We studied frequency and temperature dependencies of impedance and electric modulus of NCZF in a wide frequency range (20 Hz-5 MHz) at different measuring temperatures SM T (30-225 ℃). The complex impedance spectra clearly showed both grain and grain boundary effects on the electrical properties. The observed impedance spectra indicated that the magnitude of grain boundary resistance gb R becomes more prominent compared to grain resistance b R at room temperature, and with the increase in SM T , gb R decreases faster than the intrinsic b R . The frequency response of the imaginary part of impedance showed relaxation behavior at every SM T , and the relaxation frequency variation with SM T appeared to be of Arrhenius nature and the activation energy has been estimated to be 0.37 eV. A complex modulus spectrum was used to understand the mechanism of the electrical transport process, which indicated that a non-Debye type of conductivity relaxation characterizes this material.

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“…A c c e p t e d M a n u s c r i p t 12 relaxation process, which can be expressed as (10) where (11) is the asymptotic value of M'(ω) and (t) is the time evolution of the electric field within the material [21]. M′ and M″ are evaluated from the dielectric measurements using the following identities and (12) M' and M" values can also be written in terms of resistance and capacitance as From equation (14), we can easily see that the response peaks of the grains, grain boundary and grain electrode contact effects occur in M" at frequencies,…”

Section: Page 12 Of 30mentioning

confidence: 99%