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Number of results: 20
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Abstract

The paper reports the consequences of lanthanum modifications of barium bismuth niobiate (BaBi2Nb2O9) ceramics. The discussed materials were prepared by solid state synthesis and a one-step sintering process. The investigations are focused on dielectric aspects of the modification. The presented results reveal that the trivalent lanthanum ions incorporate twovalent barium ions, which is connected with the creation of A-site cationic vacancies as well as oxygen vacancies. Such a scenario results in significant decreasing in grain boundaries resistivity. The activation energy of grain boundaries conductivity is significantly reduced in the case of lanthanum admixture.

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Authors and Affiliations

M. Adamczyk-Habrajska
ORCID: ORCID
T. Goryczka
ORCID: ORCID
D. Szalbot
ORCID: ORCID
J. Dzik
ORCID: ORCID
M. Rerak
D. Bochenek
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Abstract

The suitability of low-cost impedance sensors for microbiological purposes and biofilm growth monitoring was evaluated. The sensors with interdigitated electrodes were fabricated in PCB and LTCC technologies. The electrodes were golden (LTCC) or gold-plated (PCB) to provide surface stability. The sensors were used for monitoring growth and degradation of the reference ATCC 15442 Pseudomonas aeruginosa strain biofilm in invitro setting. During the experiment, the impedance spectra of the sensors were measured and analysed using electrical equivalent circuit (EEC) modelling. Additionally, the process of adhesion and growth of bacteria on a sensor’s surface was assessed by means of the optical and SEM microscopy. EEC and SEM microscopic analysis revealed that the gold layer on copper electrodes was not tight, making the PCB sensors susceptible to corrosion while the LTCC sensors had good surface stability. It turned out that the LTCC sensors are suitable for monitoring pseudomonal biofilm and the PCB sensors are good detectors of ongoing stages of biofilm formation.

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Authors and Affiliations

Konrad Chabowski
Adam F. Junka
Tomasz Piasecki
Damian Nowak
Karol Nitsch
Danuta Smutnicka
Marzenna Bartoszewicz
Magdalena Moczała
Patrycja Szymczyk
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Abstract

The paper presents the family of three analyzers allowing to measure impedance in the range of 10 Ω<|Zx|<10 GΩ in a wide frequency range from 10 mHz up to 100 kHz. The most important features of the analyzer family are: miniaturization, low power consumption, low production cost, telemetric controlling and the use of an impedance measurement method based on digital signal processing (DSP). The miniaturization and other above-mentioned features of the analyzers were obtained thanks to the use of the newest generation of large-scale integration chips: e.g. “system on a chip” microsystems (AD5933), 32-bit AVR32-family microcontrollers and specialized modules for wireless communication using the ZigBee standard. When comparing metrological parameters, the developed instrumentation can equal portable analyzers offered by top worldwide manufacturers (Gamry, Ivium) but outperforms them on smaller dimensions, weight, a few times lower price and the possibility to work in a distributed telemetric network. All analyzer versions are able to be put into medium-volume production.

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Authors and Affiliations

Jerzy Hoja
Grzegorz Lentka
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Abstract

This paper adopts a fractional calculus perspective to describe a non-linear electrical inductor. First, the electrical impedance spectroscopy technique is used for measuring the impedance of the device. Second, the experimental data is approximated by means of fractional-order models. The results demonstrate that the proposed approach represents the inductor using a limited number of parameters, while highlighting its most relevant characteristics.

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Authors and Affiliations

A.M. Lopes
J.A. Tenreiro Machado
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Abstract

The main aim of the below presented work was to investigate the possibility of using impedance spectroscopy in the unpasteurized beer microbial contamination degree assessment. Advantages of the impedance spectroscopy method, a negligible number of similar published results as well as their practical aspect make the research important. Four different types of beerswere investigated whichwere unfit for consumption due to improper storage and were heavily microbiologically contaminated. Their impedance was measured in the frequency range from 0.1 Hz to 1 kHz before and after centrifugation. Based on the measured values, an innovative electrical equivalent circuit was proposed and the parameters of the circuit elements were fitted. The obtained results show significant differences (23 up to 35%) in the values of resistance modelling the diffusion phenomenon. Such large changes, resulting from the removal of biomass from the samples, prove the validity of impedance spectroscopy in the study of the properties of unpasteurized beer. According to the authors, it would be possible to use the proposed methodology during the production of beer.With some limitations, it should aid in the early detection of microbial contamination.
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Authors and Affiliations

Łukasz Macioszek
1
ORCID: ORCID
Sylwia Andrzejczak-Grzadko
2
ORCID: ORCID
Olga Konkol
2
Ryszard Rybski
1
ORCID: ORCID

  1. University of Zielona Góra, Institute of Metrology, Electronics and Computer Science, ul. prof. Z. Szafrana 2, 65-246 Zielona Góra, Poland
  2. University of Zielona Góra, Institute of Biological Sciences, ul. prof. Z. Szafrana 1, 65-516 Zielona Góra, Poland
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Abstract

In this study, the corrosion properties of Ti-6Mo-6V-5Cr-3Sn-2.5Zr alloy were investigated as a function of the cold rolling ratio and annealing temperature. The annealing treatment was carried out at temperature of 680°C, 730°C, and 780°C. The highest corrosion potential observed in the specimen with a 10% rolling ratio was 179 mV, which was more positive than that of the non-rolled specimen (–0.214 Vssc). The lowest corrosion current density (1.30×10–8 A/cm2) was observed in the non-rolled specimen which suggested that the integrity of its passive oxide layer was superior to that of the cold-rolled specimens. Time-dependent EIS evaluation revealed that the consistency of the passive oxide layer was highly affected by the subjected rolling ratio over time.

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Authors and Affiliations

Hocheol Song
Ahmad Zakiyuddin
Sinhye Kim
Kwangmin Lee
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Abstract

In this paper the method of fast impedance spectroscopy of technical objects with high impedance (|Zx| ≥1 GΩ) is evaluated by means of simulation and a practical experiment. The method is based on excitation of an object with a sinc signal and sampling the response signals proportional to current flowing through and voltage across the measured impedance. The object’s impedance spectrum is obtained with the use of continuous Fourier transform on the basis of linear approximations between samples in two acquisition sections, connected with the duration of the sinc signal. The method is first evaluated in MATLAB by means of simulation. An influence of the sinc signal duration and the number of samples on impedance modulus and argument measurement errors is explored. The method is then practically verified in a constructed laboratory impedance spectroscopy measurement system. The obtained acceleration of impedance spectroscopy in the low frequency range (below 1 Hz) and the decrease of the number of acquired samples enable to recommend the worked out method for implementation in portable impedance analyzers destined for operation in the field.

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Authors and Affiliations

Michał Kowalewski
Grzegorz Lentka
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Abstract

In this work studies ofM OVPE growth of InAlGaAs/AlGaAs/GaAs heterostructures are presented. The HRXRD and SIMS measurements indicate the high structural and optical properties as well as high uniformity oft hickness and composition ofI nAlGaAs quantum wells. This work is the .rst step towards elaboration oft he technology oft he strained InAlGaAs/GaAs heterostructures for advanced optoelectronic devices working in the visible part oft he spectrum. The investigations ofSi (n-type), Zn (p-type) .-doped GaAs epilayers and centre Si-.-doped InxGa1-xAs single quantum well (SQW) are presented. The .-doping layer was formed by SiH4 or DEZn introduction during the growth interruption. The electrical and optical properties oft he obtained structures were examined using C-V measurement, EC-V electrochemical pro.ler, Raman spectroscopy (RS), photore.ectance (PR) and photocurrent (PC) spectroscopies. Technology oft hick GaN layers grown on sapphire by HVPE is very promising as a part off reestanding GaN substrates manufacturing. Further works will be focused on the optimisation of growth, separating layers from substrates and surface polishing. The in.uence oft he growth parameters on the properties of( Ga, Al)N/Al2O3 and Mg dopant incorporation was studied.

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Authors and Affiliations

B. Boratyński
R. Korbutowicz
B. Paszkiewicz
R. Paszkiewicz
D. Pucicki
D. Radziewicz
B. Ściana
M. Tłaczała
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Abstract

Al2Cu phase has been obtained by melting pure metals in the electric arc furnace. It has been found that the intermetallic phase undergoes selective corrosion in the H3PO4 aqueous solutions. Aluminium is dissolved, the surface becomes porous and enriched with copper. The corrosion rate equals to 371 ± 17 g·m–2·day–1 (aerated solution) and 284 ± 9 g·m–2·day–1 (deaerated solution). The surface of Al2Cu phase after selective corrosion was characterised by using electrochemical impedance spectroscopy. It was found that the surface area of the specimens increases with temperature due to higher corrosion rate and is between 2137 and 3896 cm2.

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Authors and Affiliations

P. Kwolek
A. Gradzik
D. Szeliga
B. Kościelniak
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Abstract

In this paper, the effect of the resolution of an analogue-to-digital converter (ADC) on the accuracy of timedomain low-frequency electrical impedance spectroscopy is examined. For the first time, we demonstrated that different wideband stimuli signals used for impedance spectroscopy have different sensitivities to the resolution of ADC used in impedance spectroscopy systems. We also proposed Ramp and Half-Gaussian signals as new wideband stimulating signals for EIS. The effect of ADC resolution was studied for Sinc, Gaussian, Half-Gaussian, and Ramp excitation signals using both simulation and experiments. We found that Ramp and Half-Gaussian signals have the best performance, especially at low frequencies. Based on the results, a wideband electrical impedance spectroscopy circuit was implemented with a high accuracy at frequencies bellow 10 Hz.

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Authors and Affiliations

Reyhaneh L. Namin
Shahin J. Ashtiani
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Abstract

Point of present exploration was to figure out the anticorrosion activity of Acacia Cyanophylla (Saligna leaves) extract on the corrosion of mild steel in dilute sulfuric acid medium, using weight loss measurements and electrochemical impedance spectroscopy. The result of the study revealed that the extract act as a potent inhibitor on mild steel in acid medium. The increase in inhibitor concentration and immersion time showed a positive effect on inhibition efficiency. EIS exhibited one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. The increase of phase shift (n) in presence of (ACLE) lower surface roughness. This change reveals the adsorption of the inhibitor compound on the steel surface. According to the results of weight loss measurements, the adsorption of the extract on the steel surface can be described by the Langmuir isotherm. The inhibition mechanism of (ACLE) molecules involves physical interaction between the inhibitor and metal surface. Additionally, Protective film formation against acid attack was confirmed by FT-IR and AFM techniques.
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Authors and Affiliations

M. Tezeghdenti
N. Etteyeb
L. Dhouibi
O. Kanoun
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Abstract

Sodium orthovanadate was tested as a corrosion inhibitor of intermetallic Al2Cu in 1 M H3PO4. The Al2Cu – H3PO4 – Na3VO4 system was studied using the following methods: inductively coupled plasma optical emission spectrometry, scanning electron microscopy with energy dispersive x-ray spectroscopy, x-ray diffraction, electrochemical impedance spectroscopy, polarisation and open circuit potential. It was found that the corrosion rate decreased as the inhibitor concentration increased. The highest inhibition efficiency 99% was obtained when sodium orthovanadate initial concentration was equal to 100 mM, pH = 1.11, due to precipitation of a protective layer of insoluble salt, containing vanadium, phosphorus, sodium and oxygen, on the surface. At pH = 0.76 the protective layer was not formed and inhibition efficiency decreased to 76%. Selective corrosion of the intermetallic phase caused a significant increase of an electric double layer capacitance and decrease of a charge transfer resistance.

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Authors and Affiliations

P. Kwolek
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Abstract

The aim of the present work was to determine the influence of the microstructural evolution of copper single crystals with the initial orientations of <001> and <111> after cold drawing on their corrosion resistance. Transmission electron microscopy, X-ray diffraction, and electron backscattering diffraction were used to characterize the microstructural changes. To evaluate the corrosion resistance after deformation, open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization analyses were conducted. The microstructural observations showed the presence of dislocation cell structures and shear bands in deformed sample with initial orientation <001> single crystal, as well as a strongly-developed substructure in sample <111>. The material with initial orientation of <001> was more resistive in analyzed medium than material with the initial orientation of <111>.

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Authors and Affiliations

M. Koralnik
A. Dobkowska
B. Adamczyk-Cieślak
ORCID: ORCID
J. Mizera
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Abstract

Rutile-TiO2 nanorod thin films were formed on Ti disks via alkali treatment in NaOH solutions followed by heat treatment at 700°C. Ag nanoparticles were loaded on nanorods using a photo-reduction method to improve the photocatalytic properties of the prepared specimen. The surface characterization and the photo-electrochemical properties of the Ag-loaded TiO2 nanorods were investigated using a field-emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and electrochemical impedance spectroscopy (EIS). The TiO2 nanorods obtained after the heat treatment were 80 to 180 nm thick and 1 μm long. The thickness of the nanorods increased with the NaOH concentration. The UV-Vis spectra exhibit a shift in the absorption edge of the Ag-loaded TiO2 to the visible light range and further narrowing of the bandgap. The decrease in the size of the capacitive loops in the EIS spectra showed that the Ag loading effectively improved the photocatalytic activity of the TiO2 nanorods.
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Bibliography

[1] Z. Sun, J.H. Kim, Y. Zhao, F. Bijarbooneh, V. Malgras, Y. Lee, Y.M. Kang, S.X. Dou, J. Am. Chem. Soc. 133, 19314 (2011).
[2] Z.P. Tshabalala, D.E. Motaung, H.C. Swart, Phys. B Condens. Matter. 535, 227 (2018).
[3] Y. Chen, X. Li, Z. Bi, X. He, G. Li, X. Xu, X. Gao, Appl. Surf. Sci. 440, 217 (2018).
[4] Z. Yang, B. Wang, H. Cui, H. An, Y. Pan, J. Zhai, J. Phys. Chem. C 119, 16905 (2015).
[5] Y. Ren, W. Li, Z. Cao, Y. Jiao, J. Xu, P. Liu, S. Li, X. Li, Appl. Surf. Sci. 509, 145377 (2020).
[6] B. Liu, E.S. Aydil, J. Am. Chem. Soc. 131, 3985 (2009).
[7] G . Zhao, H. Kozuka, T. Yoko, Thin Solid Films 277, 147 (1996).
[8] J. Singh, K. Sahu, S. Choudhary, A. Bisht, S. Mohapatra, Ceram. Int. 46, 3275 (2020).
[9] S.L. Smitha, K.M. Nissamudeen, D. Philip, K.G. Gopchandran, Acta - Part A Mol. Biomol. Spectrosc. 71, 186 (2008).
[10] C. Wang, L. Yin, L. Zhang, Y. Qi, N. Lun, N. Liu, Langmuir 26, 12841 (2010).
[11] N.V. Long, P. Van Viet, L. Van Hieu, C.M. Thi, Y. Yong, M. Nogami, Adv. Sci. Eng. Med. 6, 214 (2013).
[12] M. Plodinec, A. Gajović, G. Jakša, K. Žagar, M. Čeh, J. Alloys Compd. 591, 147 (2014).
[13] D. Chen, Z. Jiang, J. Geng, Q. Wang, D. Yang, Ind. Eng. Chem. Res. 46, 2741 (2007).
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Authors and Affiliations

Kwangmin Lee
1
ORCID: ORCID
Daeheung Yoo
1 2
Ahmad Zakiyuddin
3
ORCID: ORCID

  1. Chonnam National University, School of Materials Science and Engineering, Gwangju 61186, Republic of Korea
  2. Quality Tech. Dept. Chosun Refractories Co., Ltd, Republic of Korea
  3. Universitas Indonesia, Department of Metallurgical and Materials Engineering, Depok 16425 Indonesia
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Abstract

Alternating current a.c. measurements enable to understand the physical and chemical processes occurring in semiconductor materials. Impedance spectroscopy has been successfully applied to study the responses of gas sensors based on metal oxides, such as TiO2, SnO2 and TiO2/SnO2 nanocomposites. This work is devoted to dynamic measurements of hydrogen sensor behaviour over the temperature range of 300–450◦C. Frequency dependence of the impedance signal gives evidence that 50 mol% TiO2/50 mol% SnO2 nanocomposites should be treated as resistive-type sensors. Temporal evolution of the response to 500 ppm H2 at 320◦C indicates a very short response time and much longer recovery.

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Authors and Affiliations

Bartłomiej Szafraniak
Anna Kusior
Marta Radecka
Katarzyna Zakrzewska
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Abstract

In this work, we present findings on the syntheses and study of properties of InSe<PTHQ> nanohybrid. The introduction of guest component in GaSe matrix leads to an increase in inhomogeneities, which is clearly confirmed by the strengthening of the low-frequency horizontal branch of Nyquist diagrams. A constant magnetic field counteracts this effect and changes the behavior of the impedance hodograph at low frequencies to the opposite. Illumination leads to a colossal increase in quantum capacitance, which is clearly demonstrated in the Nyquist diagram. For the synthesized InSe<PTHQ> nanohybrid the interesting behavior of the current-voltage characteristic is reported. As a result of studies of the synthesized InSe<PTHQ> nanohybrid the effect of “negative capacity” is observed, the magnitude of which can be controlled by the electric field. Based on the constructed impedance model and proposed N-barrier model, the physical mechanisms of the investigated processes are suggested.
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Authors and Affiliations

Fedir Ivashchyshyn
1
ORCID: ORCID
Vitaliy Maksymych
2
ORCID: ORCID
Dariusz Calus
1
ORCID: ORCID
Myroslava Klapchuk
2
ORCID: ORCID
Glib Baryshnikov
3
ORCID: ORCID
Rostislav Galagan
3
ORCID: ORCID
Valentina Litvin
3
ORCID: ORCID
Piotr Chabecki
1
ORCID: ORCID
Ihor Bordun
1 2
ORCID: ORCID

  1. Czestochowa University of Technology, Al. Armii Krajowej 17, Czestochowa, 42-200, Poland
  2. Lviv Polytechnic National University, Bandera Str. 12, Lviv, 79013, Ukraine
  3. Bohdan Khmelnytsky National University, blvd. Shevchnko 81, 18031, Cherkasy, Ukraine
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Abstract

GaSe<CS(NH 2) 2<C 14H 10>> clathrate with a hierarchical subhost<host<guest>> type architecture was formed under illumination and its electrically conductive properties were studied. The method of impedance spectroscopy studied the frequency behavior of the real and imaginary parts of the complex total impedance in the range of 10 -3-10 6 Hz. The measurements were performed under normal conditions, in a permanent magnetic field (220 kA/m), or under light illumination (for a standard solar spectrum AM 1.5 G total available power is 982 W/m 2). The structure of the impurity energy spectrum at the Fermi level was investigated by the method of thermostimulated discharge in the temperature range from 240 to 340 K. Using Jebol-Pollack theoretical approaches based on impedance spectra, the parameters of the impurity energy spectrum were calculated, such as the density of states at the Fermi level, the jump radius , the scatter of trap levels near the Fermi level and the real density of deep traps. As evidenced by studies, illumination during clathrate synthesis, forms an internal electret polarization, which leads to abnormal behavior of the photoresistive effect and to the appearance of the memristive effect. The imposition of a permanent magnetic field during the measurement of complex resistance leads to the appearance of quantum capacitance.
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Authors and Affiliations

Fedir Ivashchyshyn
1 2
ORCID: ORCID
Vitaliy Maksymych
2
ORCID: ORCID
Dariusz Calus
1
ORCID: ORCID
Dariya Matulka
2
ORCID: ORCID
Piotr Chabecki
1
ORCID: ORCID
Andrii Kunynets
2
ORCID: ORCID

  1. Czestochowa University of Technology, Al. Armii Krajowej 17, 42-200 Częstochowa, Poland
  2. Lviv Polytechnic National University, Bandera Str. 12, Lviv, 79013, Ukraine
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Abstract

In this work, we developed the lanthanum strontium cobalt ferrite and it’s composite with yttrium iron cobaltite (mass ratio of 1:1) cathodes as a thin layer on Ce0.8Sm0.2O1.9 electrolyte. Two kinds of electrode pastes were prepared, with and without 6 mm polystyrene beads as an additional pore former. The performance of cathode materials was investigated by electrochemical impedance spectroscopy as a function of electrode morphology, oxygen partial pressure, potential, and temperature. The polarization resistance of the more porous electrodes was lower than those electrodes prepared without additional pore former in the whole potential range at 800°C, slightly lower at 700°C and 600°C. The addition of yttrium iron cobaltite decreased the performance of both types of cathodes. The lower polarization resistance of porous cathodes is due to the facilitated gas diffusion through their structure.

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Authors and Affiliations

M. Mosiałek
M. Zimowska
D. Kharitonov
M. Górski
M. Krzan
A. Komenda
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Abstract

In the present paper results of the studies devoted to computer simulations of dielectric response of electroceramics in a frequency domain as well as analysis of the experimental data are given. As an object of investigations BiNbO4-based microwave ceramics was taken. Simulations of the hypothetical impedance response of the ceramic system were performed under assumption of the brick-layer model. A strategy for analysis and modelling of the impedance data for microwave electroceramics was discussed. On the base of the discussed strategy modelling of the dielectric response of BiNbO4 ceramics was performed with the electric equivalent circuit method. The Voigt’s and Maxwell’s circuits were taken as electric models. Parameters of the electric components of the circuits were determined and related to parameters of the ceramic object under study. It was found that fitting quality was good and changed within the range χ2 = 6.78 × 10–4 – 6.77 × 10–5 depending on the model.

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Authors and Affiliations

D. Czekaj
A. Lisińska-Czekaj
B. Garbarz-Glos
W. Bąk

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