A Strategy for Analysis and Modelling of Impedance Spectroscopy Data of Electroceramics: Doped Lanthanum Gallate

Ábrám, Emese; Sinclair, Derek C.; West, Anthony R.

doi:10.1023/b:jecr.0000011215.56084.87

Cited by 183 publications

(119 citation statements)

References 9 publications

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“…In order to still fit the data to an adequate equivalent circuit model, such nonideality in one specific dielectric relaxation was accounted for by using a constant-phase element (CPE) in parallel or instead of an ideal capacitor in the respective RC element. [42][43][44][45] The complex impedance Z CPE * of a CPE is defined as…”

Section: Nonideal Dielectric Responsementioning

confidence: 99%

Magnetoimpedance spectroscopy of epitaxial multiferroic thin films

et al. 2012

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The detection of true magnetocapacitance (MC) as a manifestation of magnetoelectric coupling (MEC) in multiferroic materials is a nontrivial task, because pure magnetoresistance (MR) of an extrinsic MaxwellWagner-type dielectric relaxation can lead to changes in capacitance [G. Catalan, Appl. Phys. Lett. 88, 102902 (2006)]. In order to clarify such difficulties involved with dielectric spectroscopy on multiferroic materials, we have simulated the dielectric permittivity ε of two dielectric relaxations in terms of a series of one intrinsic film-type and one extrinsic Maxwell-Wagner-type relaxation. Such a series of two relaxations was represented in the frequency-(f -) and temperature-(T -) dependent notations ε vs f and ε vs T by a circuit model consisting in a series of two ideal resistor-capacitor (RC) elements. Such simulations enabled rationalizing experimental f -, T-, and magnetic field-(H -) dependent dielectric spectroscopy data from multiferroic epitaxial thin films of BiMnO 3 (BMO) and BiFeO 3 (BFO) grown on Nb-doped SrTiO 3 . Concomitantly, the deconvolution of intrinsic film and extrinsic Maxwell-Wagner relaxations in BMO and BFO films was achieved by fitting f -dependent dielectric data to an adequate equivalent circuit model. Analysis of the H -dependent data in the form of determining the H -dependent values of the equivalent circuit resistors and capacitors then yielded the deconvoluted MC and MR values for the separated intrinsic dielectric relaxations in BMO and BFO thin films. Substantial intrinsic MR effects up to 65% in BMO films below the magnetic transition (T C ≈ 100 K) and perceptible intrinsic MEC up to − 1.5% near T C were identified unambiguously.

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Section: Nonideal Dielectric Responsementioning

confidence: 99%

Magnetoimpedance spectroscopy of epitaxial multiferroic thin films

et al. 2012

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“…The impedance spectrum normally separates bulk, grain boundary, and electrode processes of the ceramics. The high frequency semicircle in the impedance complex plane comes from the bulk conduction and dielectric process; the intermediate frequency semicircle is due to the grain boundary response, and the low frequency arc is attributed to electrode processes [6,8,9]. The impedance data can be analyzed by a simple hand fitting process [6], while a more quantitative approach uses an electrical equivalent circuit to model the spectrum and extract parameters [8].…”

Section: Impedance Spectramentioning

confidence: 99%

“…The impedance data can be analyzed by a simple hand fitting process [6], while a more quantitative approach uses an electrical equivalent circuit to model the spectrum and extract parameters [8]. Abram et al [8] compared various equivalent circuits to model the impedance response of the LSGM ceramic. It was suggested that a suitable equivalent circuit is necessary in order to obtain parameters with physical significance.…”

Section: Impedance Spectramentioning

confidence: 99%

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Preparation and characterisation of perovskite La0.8Sr0.2Ga0.83Mg0.17O2.815 electrolyte using a poly(vinyl alcohol) polymeric method

Yang

2016

J Adv Ceram

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Abstract:The perovskite La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 2.815 (LSGM) fuel cell electrolyte was prepared by a polymeric method using poly(vinyl alcohol) (PVA). The LSGM precursor powder was examined by thermogravimetric and differential thermal analysis (TG/DTA) and Fourier transform infrared (FTIR) spectroscopy. It was found that thermal decomposition of the LSGM precursor powder occurs in a number of different stages, and complete decomposition of the precursor is obtained at 1000 ℃. X-ray diffraction (XRD) showed that calcined powder contains three secondary phases, namely La 4 Ga 2 O 9 , LaSrGa 3 O 7 , and LaSrGaO 4 , even after calcination at 1100 ℃. Furthermore, the fraction of secondary phases decreases with increasing calcination temperature. Single phase perovskite LSGM pellets with a relative density of 97% were obtained after sintering at 1450 ℃ for 10 h. It was therefore shown that the powder prepared by the simple PVA method is fine, highly reactive, and sinterable. The electrical properties of LSGM pellets were characterised by impedance spectroscopy. The conductivity of the LSGM pellets sintered at 1450 ℃ for 10 h was 8.24×102 S/cm at 800 ℃.

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“…The slightly flattened semi-circular shape complicates the interpretation of the Nyquist plots a little and indicates a dispersion of the RC time constant, which is typical of a polycrystalline material with a distribution of interfacial resistance and capacitance [23]. Strictly, in such cases a more complex equivalent circuit that includes a constant phase element is required in order to provide an accurate interpretation of the IS data [24]. However, for the present application the simplified circuit described above was considered sufficient to determine the relative magnitudes of the grain boundary and grain bulk resistances.…”

Section: Impedance Spectroscopy Experimentsmentioning

confidence: 99%

Development of a Reusable Atomic Oxygen Sensor Using Zinc Oxide Thick Films

et al. 2013

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1 The paper describes the fabrication and testing of thick film zinc oxide sensors that could be used to monitor the atomic oxygen fluence experienced by spacecraft in low Earth orbit, or that produced in ground-based atomic oxygen sources. Impedance spectroscopy measurements were carried out on the sensors to determine the conduction mechanisms within the thick films when exposed to atomic oxygen. The results indicate that the sensors' total resistance increases linearly with time when they are exposed to a constant flux of atomic oxygen, and that the sensors can be regenerated by heating.Index Terms-Atomic Oxygen, Space Environment, Thick film sensors, Zinc Oxide. I. INTRODUCTIONAtomic oxygen (AO) is the main atmospheric constituent in Low Earth Orbit (LEO) at altitudes between 200-1000 km. Atomic oxygen is formed by the photo-dissociation of molecular oxygen by solar ultra-violet (UV) radiation [1]; at these altitudes the probability of recombination is low due to the low atmospheric density and hence the AO is a stable species. Despite its low density it is well known [2] that AO causes high levels of damage over time to many spacecraft materials, particularly those located on forward-facing (ram direction) surfaces. For example, silver electrical contacts are readily oxidised and become non-conducting whilst polymer thermal protection blankets may be eroded, causing their optical properties (emissivity and absorptivity) to change and thus affecting their performance. In both cases the damage processes are enhanced by the high collision energy (approx. 5 eV) of the AO. The AO flux (usually expressed as atoms cm -2 s -1 ) is highly variable, depending primarily on altitude and level of solar activity [1].As an example, for the International Space Station (ISS), residing in a roughly 330 km circular orbit, a typical AO flux J.C. Valer was a doctoral student at the University of Southampton. His contact details are:1 Rowleys Mill,

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A Strategy for Analysis and Modelling of Impedance Spectroscopy Data of Electroceramics: Doped Lanthanum Gallate

Cited by 183 publications

References 9 publications

Magnetoimpedance spectroscopy of epitaxial multiferroic thin films

Magnetoimpedance spectroscopy of epitaxial multiferroic thin films

Preparation and characterisation of perovskite La0.8Sr0.2Ga0.83Mg0.17O2.815 electrolyte using a poly(vinyl alcohol) polymeric method

Development of a Reusable Atomic Oxygen Sensor Using Zinc Oxide Thick Films

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