Vogel–Fulcher analysis of relaxor dielectrics with the tetragonal tungsten bronze structure: Ba6MNb9O30 (M = Ga, Sc, In)

Rotaru, Andrei; Morrison, Finlay D.

doi:10.1007/s10973-014-4355-5

Cited by 27 publications

(20 citation statements)

References 65 publications

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“…In previous research, temperature-dependent powder neutron diffraction (TDPND) and microstructural characterisation by scanning electron microscopy (SEM) confirmed the nature of the phases formed and contributed to their crystallographic identification [41]. Moreover, the origin of the polar response and the nature of the relaxor behaviour were established by combining the results of the structural investigations with the dielectric properties inspected by immittance spectroscopy (IS) [7,41], whilst the dynamics of dielectric relaxation of dipoles was understood by fitting the dielectric data (permittivity and loss) with the VogelFulcher (VF) and the universal dielectric response (UDR) models [42].…”

Section: Introductionmentioning

confidence: 85%

“…For obtaining Ba 6 GaNb 9 O 30 pellets, the powders were pressed in a 10-mm-diameter uniaxial stainless steel die to 1 tonne, producing a pressure of around 200 MPa followed by sintering in a tube furnace for 12 h at 1250°C (heating and cooling rates were of 10 K min -1 ). Phase formation was confirmed by powder X-ray diffraction and temperature-dependent powder neutron diffraction; at room temperature, diffraction data were refined with the centrosymmetric tetragonal space group P4/mbm [5,41,42].…”

Section: Methodsmentioning

confidence: 99%

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Elastic and anelastic relaxations accompanying relaxor ferroelectric behaviour of Ba6GaNb9O30 tetragonal tungsten bronze from resonant ultrasound spectroscopy

Rotaru

Schiemer

Carpenter

2016

J Therm Anal Calorim

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Tetragonal tungsten bronze (TTB) structures offer some promise as lead-free ferroelectrics and have an advantage of great flexibility in terms of accessible composition ranges due to the number of crystallographic sites available for chemical substitution. The ferroic properties of interest are coupled with strain, which will be important in the context of stability, switching dynamics and thin film properties. Coupling of strain with the ferroelectric order parameter gives rise to changes in elastic properties, and these have been investigated for a ceramic sample of Ba 6 GaNb 9 O 30 (BGNO) by resonant ultrasound spectroscopy. Room temperature values of the shear and bulk moduli for BGNO are rather higher than for TTBs with related composition which are orthorhombic at room temperature, consistent with suppression of the ferroelectric transition. Instead, a broad, rounded minimum in the shear modulus measured at *1 MHz is accompanied by a broad rounded maximum in acoustic loss near 115 K and signifies relaxor freezing behaviour. Elastic softening with falling temperature from room temperature, ahead of the freezing interval, is attributed to the development of dynamical polar nanoregions (PNRs), whilst the nonlinear stiffening below *115 K is consistent with a spectrum of relaxation times for freezing of the PNR microstructure.

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Section: Introductionmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 99%

Elastic and anelastic relaxations accompanying relaxor ferroelectric behaviour of Ba6GaNb9O30 tetragonal tungsten bronze from resonant ultrasound spectroscopy

Rotaru

Schiemer

Carpenter

2016

J Therm Anal Calorim

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“…The frequency dependence of the temperature of maximum permittivity, T m , in relaxors can be described by the VogelFulcher law (4) which provides some insights into the dynamics of dielectric relaxation [39][40][41].…”

Section: Dielectric and Relaxor Ferroelectric Propertiesmentioning

confidence: 99%

Electrophysical properties of the multicomponent PBZT-type ceramics doped by Sn4+

et al. 2018

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In the work, the multicomponent Pb 0.75 Ba 0.25 (Zr 0.65 Ti 0.35 ) 1-a Sn a O 3 (PBZT/Sn) ceramics were obtained with various tin amounts (a from the range of 0.0 to 0.1). The densification of the PBZT/Sn ceramic samples was performed using pressureless sintering method. The effect of SnO 2 content on the crystal structure of PBZT/Sn ceramics, microstructure, DC electrical conductivity and electrophysical properties (including dielectric and ferroelectric testes), were investigated. The PBZT/Sn ceramic samples exhibit high values of dielectric permittivity at the temperature of ferro-paraelectric phase transition and show the relaxor character of phase transition. Excessive SnO 2 contents doping of the PBZT/Sn materials (already for a = 0.1) might lead to lattice stress and structure defects, which successively leads to the deterioration of ferroelectric and dielectric properties of the ceramic samples. The presented research shows that the addition of SnO 2 to the base PBZT compound (in the proper proportion) gives an additional possibility of influencing the parameters essential for practical applications, from the areas of micromechatronics and microelectronics.

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“…We have shown that Vogel-Fulcher fits are very sensitive. Constraining some of the fundamental relaxation parameters to physically sensible values or varying the fitting range itself, results in a large range of values associated with the dielectric relaxation processes; restriction of the frequency domain due to experimental noise or instrumentation limits also has a dramatic influence on the values obtained [40].…”

Section: Introductionmentioning

confidence: 99%

Microstructural and high-temperature impedance spectroscopy study of Ba6MNb9O30 (M=Ga, Sc, In) relaxor dielectric ceramics with tetragonal tungsten bronze structure

Rotaru

Morrison

2016

Ceramics International

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Cite this article as: Andrei. Rotaru and Finlay D. Morrison, Microstructural and high-temperature impedance spectroscopy study of Ba 6 MNb 9 O 30 (M=Ga, Sc, In) relaxor dielectric ceramics with tetragonal tungsten bronze structure, Ceramics International, http://dx.doi.org/10. 1016/j.ceramint.2016.04.102 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. poorer microstructure, with many small and poorly-bonded grains gathered in agglomerates, resulting in significant continuous porosity and poorly defined grain boundary regions. The electroactive regions were characterised by the bulk and grain boundaries capacitances and resistances, while their contribution to the electrical conduction process was estimated by determining activation energies from the temperature (Arrhenius) dependence of both electric conductivities and time constants. For Ga and In analogues the electronic conductivity are dominated by the bulk response, while for Sc analogue, the poorly defined grain boundariesgive a bulk-like response, mixing with the main bulk contribution.

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Vogel–Fulcher analysis of relaxor dielectrics with the tetragonal tungsten bronze structure: Ba6MNb9O30 (M = Ga, Sc, In)

Cited by 27 publications

References 65 publications

Elastic and anelastic relaxations accompanying relaxor ferroelectric behaviour of Ba6GaNb9O30 tetragonal tungsten bronze from resonant ultrasound spectroscopy

Elastic and anelastic relaxations accompanying relaxor ferroelectric behaviour of Ba6GaNb9O30 tetragonal tungsten bronze from resonant ultrasound spectroscopy

Electrophysical properties of the multicomponent PBZT-type ceramics doped by Sn4+

Microstructural and high-temperature impedance spectroscopy study of Ba6MNb9O30 (M=Ga, Sc, In) relaxor dielectric ceramics with tetragonal tungsten bronze structure

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