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  1. 29 Materials Science Poland
  2. 18 Archives of Metallurgy and Materials
  3. 13 Ceramic Materials
  4. 13 Materiały Ceramiczne
  5. 5 Scientific Bulletin. Physics / Lodz University of Technology
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  1. 10 Czekaj D.
  2. 6 Bochenek D.
  3. 6 Bąk W.
  4. 6 Lisińska-Czekaj A.
  5. 5 Kajtoch C.
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  1. 2 2023
  2. 3 2021
  3. 9 2020
  4. 5 2019
  5. 7 2018
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1
Content available remote The influence of the electrode material on the dielectric properties of PET films
Łowkis Bożena, Ziaja Jan, Kraft Aleksandra Anna
Przegląd Elektrotechniczny
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2023
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R. 99, nr 1
58--61
EN
This paper presents the influence of the measuring electrode material on the dielectric properties of polyethylene terephthalate. We show that volume resistivity, surface resistivity, relative permittivity and the dielectric loss factor of PET films are a function of the electrode material used. We also evaluate the effect of thermal aging on the tested material parameters.
PL
Przedstawiono wpływ materiału elektrod pomiarowych na właściwości dielektryczne politereftalanu etylenu. Stwierdzono, że rezystywność skrośna, rezystywność powierzchniowa, względna przenikalność elektryczna oraz współczynnik strat dielektrycznych folii PET są funkcją zastosowanego materiału elektrod. Oceniono wpływ starzenia termicznego na badane parametry materiałowe.
2
Content available Novel multicomponent functionalized biopolymers with enhanced thermal and dielectric properties
Rani Sanjeeta, Ali Syed Kashif, Kumar Pawan, Anugrah Kunwar Sugam, Saya Laishram, Gambhir Geetu, Gautam Drashya, Hooda Sunita, Verma Manisha
Polimery
|
2023
|
Vol. 68, nr 7-8
386--395
EN
A new functionalized biopolymer was obtained by modifying chitin using ethylenediaminetetraacetic acid and magnetite nanoparticles (Fe3O4). Thermogravimetric analysis was performed, and dielectric properties were examined. The obtained biopolymer showed better thermal stability, as evidenced by a higher onset temperature. The activation energy calculated using imaginary impedance data and Nyquist plots was found to be consistent. Moreover, the dielectric permittivity decreased rapidly with increasing frequency. At high frequencies, there was no dependence of dielectric loss on temperature and frequency. The obtained biopolymer can be used in many applications such as microwave devices, deflection yoke, high-frequency capacitors, sensors, etc.
PL
Otrzymano nowy funkcjonalizowany biopolimer poprzez modyfikację chityny przy użyciu kwasu etylenodiaminotetraoctowego i nanocząstek magnetytu (Fe3O4). Przeprowadzono analizę termograwimetryczną i zbadano właściwości dielektryczne. Otrzymany biopolimer wykazywał lepszą stabilność termiczną, o czym świadczyła wyższa temperatura początku rozkładu. Wykazano zgodność energii aktywacji obliczonej z wykorzystaniem danych dotyczących urojonej impedancji oraz na podstawie wykresów Nyquista. Przenikalność dielektryczna zmniejszała się gwałtownie wraz ze wzrostem częstotliwości. Przy wysokich częstotliwościach nie stwierdzono zależności stratności dielektrycznej od temperatury i częstotliwości. Otrzymany biopolimer można wykorzystać w wielu zastosowaniach, takich jak urządzenia mikrofalowe, jarzmo odchylające, kondensatory wysokiej częstotliwości, czujniki itp.
3
Nowe metody charakteryzacji materiałów dielektrycznych w zakresie mikrofalowym oraz fal milimetrowych
Karpisz Tomasz
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2021
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nr 4
101--105
PL
Artykuł jest poświęcony rozwojowi jednowymiarowego, skalarnego, wielowarstwowego, elektromagnetycznego modelu otwartego rezonatora Fabry-Perot, wykorzystanego do pomiarów własności elektromagnetycznych elektrycznie cienkich warstw dielektryków na częstotliwości od 20 do 110 GHz. Pokrótce omówiono podstawy teoretyczne metody opisującej zachowanie fali elektromagnetycznej w otwartym rezonatorze Fabry-Perot oraz proces projektowania takiego układu pomiarowego. Następnie przedstawiono układ pomiarowy, kolejno zaprezentowano niektóre z wyników pomiarów wykonanych podczas prac związanych z doktoratem autora publikacji. Pod koniec omówiono ograniczenia omawianej metody oraz możliwe ścieżki rozwoju.
EN
This paper is focused on the introduction of a one-dimensional scalar multi-layer electromagnetic model of a Fabry-Perot open resonator and its use in the measurement of electromagnetic properties of electrically thin dielectric sheet materials in frequencies from 20 to 110 GHz. Short theoretical description of an electromagnetic wave inside resonator have been described. Furthermore, results of measurement for frequencies exceeding 50 GHz have been shown as well as unique capability of measurement of the samples with in-plane anisotropy. In the end measurement system limitation have been discussed with possibilities for further system development.
4
Content available The Effect of Ho Doping Contents on the Structural, Microstructure and Dielectric Properties of Bi5Ti3FeO15 Aurivillius Ceramics
Tomaszewska M., Dzik J., Wodecka-Duś B., Pikula T., Adamczyk-Habrajska M., Szalbot D., Chocyk D.
Archives of Metallurgy and Materials
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2021
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Vol. 66, iss. 1
91--96
EN
Aurivillius Bi5-xHoxTi3FeO15 (BHTFO) multiferroic ceramics with different holmium doping contents were synthesized by conventional solid state reaction. The effect of holmium doping on the microstructure, structural and dielectric behaviors of BHTFO ceramics were investigated in details. Microstructure and crystalline structure studies of ceramics were carried out at room temperature while dielectric properties were investigated in a wide range of temperature (T = 25ºC-550ºC) and frequency (20Hz-1MHz).
5
Content available Synthesis and Dielectric Properties of Nd Doped Bi5Ti3FeO15 Ceramics
Kocoń N., Dzik Jolanta, Szalbot Diana, Pikula Tomasz, Adamczyk-Habrajska Małgorzata, Wodecka-Duś Beata
Archives of Metallurgy and Materials
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2021
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Vol. 66, iss. 2
359--365
EN
Aurivillius Bi5Ti3Feo15 (BTF) and Bi5-xNdxTi3Feo15 (BNTF) ceramics were successfully synthesized by a simple solid state reaction method. Ceramics were prepared from simple oxide powders Bi2O3, TiO2, Nd2O3 and Fe2O3. The microstructure, structure, chemical composition and dielectric properties of the obtained materials were examined. Dielectric properties were investigated in a wide range of temperatures (T = 25ºC-550ºC) and frequencies (20Hz-1MHz).
6
Content available remote Microwave synthesis of Zn:Mn:PbI2 micro-size nanosheets and their characterizations
Shkir Mohd., Al-Kotb M. S., Yahia I. S., Alshahrani T., AlFaify S., Abutalib M. M.
Materials Science Poland
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2020
|
Vol. 38, No. 2
367--373
EN
Herein, we are reporting, for the first time, a microwave-assisted synthesis of lead iodide (PbI2) nanosheets (NSs) with codoping of Zn and Mn, confirmed by SEM/EDX. In the co-doping Mn concentration was kept at a constant level (i.e. 15 %) while Zn concentration was varied from 1 wt.% to 10 wt.%. The morphological analysis confirming presence of the dopant was done through SEM/EDX. The single phase and polytypic nature of NSs were established by XRD and FT-Raman examinations. Homogeneous doping of Mn and Zn in prepared PbI2 NSs was confirmed by SEM mapping analysis. The dielectric and electrical properties were measured by preparing a compact pellet of NSs at 49820 Pa pressure. The dielectric constant and electrical conductivity were enhanced by Zn:Mn co-doping in PbI2. The radiation activity was tested by cesium-137 (137Cs) radioactive source and its increase resulting from the doping was observed. The enhanced properties suggest that the prepared NSs may be useful in electro-optic and radiation detection device applications.
7
Content available remote Influence of cation order on the dielectric properties of (1 – x)Pb(Sc0.5Nb0.5)O3-xPb(Yb0.5Nb0.5)O3 ceramics
Garbarz-Glos Barbara, Bąk Wojciech, Antonova Maija, Kalvane Anna, Kajtoch Czesław, Dulian Piotr
Materials Science Poland
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2020
|
Vol. 38, No. 3
402--406
EN
Ceramic lead niobates and their solid solutions of (1 – x)Pb(Sc0.5Nb0.5)O3-xPb(Yb0.5Nb0.5)O3 were synthesized by solid state reactions from oxides. The structure of investigated samples was characterized by X-ray diffraction (XRD). Dielectric studies of the ceramics were performed by means of broadband dielectric spectroscopy at the temperature ranging from 600 K to 140 K. For all ceramic samples a diffuse phase transition as well as relaxor ferroelectric behavior were observed.
8
Content available remote Effect of L-asparagine as dopant on the growth and characteristics of ammonium tetroxalate dihydrate single crystal
Jerusha Eunice, Kirupavathy S. Shahil
Materials Science Poland
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2020
|
Vol. 38, No. 1
48--61
EN
Single crystals of L-asparagine doped ammonium tetroxalate dihydrate were grown using slow evaporation solution growth technique with deionized water as a solvent. The shift and intensity of the peaks in the single crystal X-ray diffraction and Fourier transform infrared analyses confirmed the inclusion of L-asparagine in the ammonium tetroxalate dihydrate crystal structure. The optical transmission characteristics viz. optical band gap, optical conductivity, etc., were determined. Thermal studies revealed the occurrence of anomalies at 135.3 °C and 221.7 °C leading to the possibility of phase transitions and thereby, ferroelectric behavior. Vickers microhardness studies enabled determination of various microhardness parameters. Dielectric behavior was analyzed by varying the temperature and frequency. Anomalies were observed at 135 °C and 221 °C suggesting the existence of ferroelectric nature of the compound. Self-defocusing effect was observed. The polarization-electric field hysteresis loops showed a pinched effect due to defects induced by inclusion of dopant. The crystals were characterized by single crystal XRD, FT-IR, DRS, UV-Vis-NIR, Vickers microhardness test as well as thermal and dielectric techniques. In brief, L-asparagine as a dopant in ammonium tetroxalate dihydrate altered various physical properties of the crystals. They were highly transparent in the visible region with a wider optical band gap, softer material than the parent, higher phase transition temperature of 135 °C, negative nonlinearity and self-defocusing ability.
9
Content available Study on the Electromagnetic and Mechanical Properties of Coated Composites
Liu Yuanjun, Wang Huanhuan, Zhang Yiqu, Wang Xichen, Yin Guang, Han Xiaohui, Niu Jiarong
Fibres & Textiles in Eastern Europe
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2020
|
Vol. 28, no. 6 (144)
89--97
EN
In this paper, a single-layer coated composite was prepared using PU2540 polyurethane as the matrix, nickel powder as the wave-absorbing functional particle, and coating technology on plain cotton fabric. The influence of the content of nickel powder on the dielectric properties (the real and imaginary parts and the loss tangent value), the shielding effectiveness and the mechanical properties was studied adopting the method of controlling variables. The result showed that when the content of nickel powder was 0~20% and that of nickel powder relative to that of polyurethane was 20%, the real and imaginary parts of the dielectric constant of the coating were the largest, and its polarising and loss ability with respect to electromagnetic waves were the strongest; when the content of nickel powder relative to that of polyurethane was 15%, the loss tangent value of the coating was the largest, and its absorption and attenuation ability with respect to electromagnetic waves was the strongest. When the values of the coating thickness were at 0.5~2 mm, the real and imaginary parts of the dielectric constant of the coating with a thickness of 1 mm were the largest, and the polarising and loss ability with respect to electromagnetic waves were the strongest. When the loss tangent value and the shielding-attenuation value of the coating with a thickness of 2 mm were the largest, the absorbing-attenuation and shielding-attenuation ability with respect to electromagnetic waves were the strongest.
PL
W pracy wykonano jednowarstwowy kompozyt powlekany z poliuretanu PU2540 jako matrycy i proszku niklowego jako cząstki funkcjonalnej pochłaniającej fale. Przyjmując metodę regulacji zmiennych zbadano wpływ zawartości proszku niklowego na właściwości dielektryczne (części rzeczywiste i urojone oraz wartość stycznej strat) i skuteczność ekranowania oraz właściwości mechaniczne. Wyniki pokazały, że w przypadku zawartości proszku niklu w stosunku do zawartości poliuretanu wynoszącej 20%, rzeczywiste i urojone części stałej dielektrycznej powłoki były największe, a jej polaryzacja w odniesieniu do fal elektromagnetycznych była najsilniejsza. Gdy zawartość proszku niklu w stosunku do poliuretanu wynosiła 15%, wartość stycznej straty powłoki była największa, a jej zdolność pochłaniania i tłumienia fal elektromagnetycznych była największa. Gdy wartości grubości powłoki wynosiły 0,5~2 mm, rzeczywiste i urojone części stałej dielektrycznej powłoki o grubości 1 mm były największe, a polaryzacja w odniesieniu do fal elektromagnetycznych była najsilniejsza. Gdy wartość styczna strat i wartość tłumienia ekranowania powłoki o grubości 2 mm były największe, to zdolność tłumienia absorpcji i tłumienia ekranowania fal elektromagnetycznych była najsilniejsza.
10
Content available Influence of Wave-Absorbing Functional Particles on the Electromagnetic Properties and Mechanical Properties of Coated Composites for Nickel Powders
Liu Yuanjun, Wang Yi, Wu Xiang, Zhang Lulu, Niu Jiarong
Fibres & Textiles in Eastern Europe
|
2020
|
Vol. 28, no. 5 (143)
75--81
EN
In this subject, a single-layer coated composite for nickel powders was prepared using PU2540 polyurethane as the matrix, nickel powder as the wave-absorbing functional particle, and coating technology on plain cotton fabric. The influence of wave-absorbing functional particles on the dielectric, shielding effectiveness and mechanical properties of the single-layer coated composite for nickel powders was mainly analysed and compared. Results showed that the real and imaginary parts and loss tangent of the dielectric constant were all the largest when the iron powder was mixed with the nickel powder, and its polarizing ability, loss ability and attenuation ability with respect to electromagnetic waves were all the maximum. When the graphene was mixed with the nickel powder, the shielding attenuation ability with respect to electromagnetic waves was the best.
PL
W ramach pracy przygotowano jednowarstwowy kompozyt powlekany żywicą poliuretanową zawierającą proszek niklu. Do przygotowania kompozytów użyto poliuretanu PU2540 jako matrycy i proszku niklu jako absorbującej fale cząstki funkcjonalnej oraz zastosowano technologię powlekania na gładkiej tkaninie bawełnianej. Przeanalizowano i porównano głównie wpływ absorbujących fale funkcjonalnych cząstek na dielektryk, skuteczność ekranowania i właściwości mechaniczne jednowarstwowego powlekanego kompozytu. Wyniki pokazały, że rzeczywiste i urojone części oraz styczna strat stałej dielektrycznej były największe, gdy proszek żelaza został zmieszany z proszkiem niklu, a jego zdolność polaryzacyjna, zdolność do strat i zdolność tłumienia fal elektromagnetycznych były maksymalne. Gdy grafen został zmieszany z proszkiem niklu, zdolność tłumienia ekranowania fal elektromagnetycznych była najlepsza.
11
Content available The Application of the Mechanochemical Synthesis for the Preparation of Advanced Ceramics Based on Barium Titanate
Garbarz-Glos B., Bąk W., Budziak A., Dulian P., Lisińska-Czekaj A., Czekaj D.
Archives of Metallurgy and Materials
|
2020
|
Vol. 65, iss. 4
1391--1396
EN
In the present study, the lead-free BaTi1-x Zrx O3 (for x = 0, 0.05 and 0.15) ceramics were prepared by High-Energy Ball Milling and heat treatments. The performed X-ray, SEM and EDS measurements confirmed high purity, good quality and the expected quantitative composition of the obtained samples. The study of dielectric properties was performed by means of broadband dielectric spectroscopy at the frequency ranging from 0.1 Hz to 10 MHz. The obtained measurement data, analyzed in accordance with the Arrhenius formalism demonstrated the presence of relaxation type dielectric mechanisms. The impedance answer of studied ceramic materials indicated the presence of two relaxation processes: one with a dominant resistive component and the other with a small capacitive component. The observed dielectric relaxation process is temperature dependent and has a “non-Debye” character.
12
Content available Properties of Pb1-xBax(Zr1-yTiy)1-zSnzO3 (x = 0.03, y = 0.02, z = 0÷0.08) Ceramics
Brzezińska D.
Archives of Metallurgy and Materials
|
2020
|
Vol. 65, iss. 2
975--982
EN
This paper presents the results of obtaining and investigations of Pb1-xBax(Zr1-yTiy)1-zSnzO33(PBZTS) ceramics with constant x = 0.03 and y = 0.02, and variable z = 0, 0.04, 0.06 and 0.08 (abbreviations of the samples were following PBZTS0, PBZTS4, PBZTS6, PBZTS8, respectively). The investigated compositions are close to rhombohedral-orthorhombic morphotropic phase boundary. The ceramic samples have been obtained by conventional ceramic technology from simple oxides PbO, ZrO2, TiO2, SnO2 and barium carbonate BaCO3. The ceramic powders, after calcination, have been pressed into discs and sintered using free sintering (FS) method. For samples obtained in such a way, the dielectric properties at various frequencies and electrical conductivity have been investigated. The increase of Sn content orders the microstructure of ceramics, and as a result the improvement of the dielectric properties of ceramic samples can be obtained.
13
Content available Correlation Between Structure, Microstructure and Dielectric Properties of Bi7Fe3Ti3O21 Ceramics Obtained in Different Conditions
Szalbot D., Bartkowska J. A., Feliksik K., Bara M., Chrunik M., Adamczyk-Habrajska M.
Archives of Metallurgy and Materials
|
2020
|
Vol. 65, iss. 2
879--884
EN
Multiferroic six-layer Aurivillius type Bi7Fe3Ti3O21 ceramics was obtained by conventional mixed oxides method. The final sintering process was taken in several different sintering times, which determined changes in properties of discussed ceramic material. The structure and dielectric properties of the material are reported. In order to examine the technological conditions on the crystal structure, XRD analysis was carried out. The microstructure, as well as the quantitative and qualitative analysis of the chemical composition were investigated by scanning electron microscope with an energy dispersion spectrometer. The main purpose of the paper is to present the effect of sintering time on the microstructure, crystallographic structure and dielectric properties of Bi7Fe3Ti3O21 ceramics.
14
Content available Alternative, Direct Synthesis Method of the Ceramic Solid Solutions Based on BaTiO3 Through a High Energy Ball Milling
Bąk W., Dulian P., Garbarz-Glos B., Czekaj D., Lisińska-Czekaj A.
Archives of Metallurgy and Materials
|
2020
|
Vol. 65, iss. 2
805--810
EN
Polycrystalline samples BaTiO3 and the solid solutions Ba0.9 Sr0.1 TiO3, 0.9 Sr0.1 Ti0.9 Sn0.1 O3, Ba0.9 Sr0.1 Ti0.8 Sn0.2 O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure and morphology of the investigated samples were characterized by an X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization of electrical properties of the ceramics within the temperature range from –130°C to 250°C were performed by means of a dielectric spectroscopy method at the frequency ranging from 0.1 Hz to10 MHz. The diffusion of the paraelectric – ferroelectric phase transition and dielectric relaxation for ceramic samples are described.
15
Content available remote Structural and electrical properties of Nb-doped Bi7Ti4.5W0.5O21 intergrowth piezoelectric ceramics
Zhuang Junsheng, Jiang Xiangping, Chen Chao, Jiang Xingan, Huang Xiaokun, Nie Xin, Jiang Yujian
Materiały Ceramiczne
|
2019
|
T. 71, nr 4
341--349
EN
New layer-structured lead-free piezoelectric ceramics Bi7Ti4.5-xW0.5NbxO21 (BTW-BIT-xNb) (0.00 ≤ x ≤ 0.50) with high Curie temperature TC (up to 690 ℃) have great potential for high temperature applications. However, this material system receives far less attention by researchers due to its poor piezoelectric performance. In the present study, the crystal structure, microstructure and electrical properties of samples with different content of Nb were studied detailedly. The structural characterization by XRD patterns Rietveld refinements and Raman scattering analysis shows that Nb5+ substituted for B-site Ti4+ ion located in the pseudo perovskite blocks and enhanced the orthorhombic distortion, leading to the increasing Curie temperature in the range of 692-762 ℃. The substitution of Nb5+ for Ti4+ acts as donor doping, which effectually reduces the amount of oxygen vacancies, and consequently lowers dielectric loss tgδ. The piezoelectric properties of Nb-doped samples were improved with a maximum piezoelectric constant d33 of 14.3 pC/N obtained in BTW-BIT-0.05Nb sample, which is approximately double that of pure BTW-BIT (~7.3 pC/N). Above results reveal that Nb doped BTW-BIT ceramic system overcomes the difficult coordination between piezoelectric performances and Curie temperature, and realizes the common enhancement of piezoelectric performances and Curie temperature, which is of great value for promoting the practical application of high-temperature piezoelectric ceramics
PL
Nowa bezołowiowa ceramika piezoelektryczna o strukturze warstwowej Bi7Ti4,5-xW0,5NbxO21 (BTW-BIT-xNb) (0,00 ≤ x ≤ 0,50) z wysoką temperaturą Curie TC (do 690 ℃) ma ogromny potencjał do zastosowań w wysokich temperaturach. Jednak ten system materiałowy cieszy się znacznie mniejszym zainteresowaniem ze względu na słabą wydajność piezoelektryczną. W niniejszym badaniu szczegółowo zbadano strukturę krystaliczną, mikrostrukturę i właściwości elektryczne próbek o różnej zawartości Nb. Charakterystyka strukturalna za pomocą analizy Rietvelda dyfraktogramów rentgenowskich i analiza rozpraszania Ramana pokazują, że Nb5+ zastąpił jon Ti4+ w miejscu B znajdujący się w blokach pseudoperowskitu i zwiększył zniekształcenie rombowe, prowadząc do wzrostu temperatury Curie w zakresie 692-762 ℃. Zastąpienie Ti4+ przez Nb5+ działa jak domieszkowanie donorowe, co skutecznie zmniejsza ilość wakancji tlenowych, a tym samym obniża straty dielektryczne tanδ. Właściwości piezoelektryczne próbek domieszkowanych Nb zostały poprawione dzięki maksymalnej stałej piezoelektrycznej d33 wynoszącej 14,3 pC/N, uzyskanej w próbce BTW-BIT-0,05Nb, która jest w przybliżeniu dwukrotnie większa niż czystej BTW-BIT (~7,3 pC/N). Powyższe wyniki pokazują, że system ceramiczny BTW-BIT z domieszką Nb przezwycięża trudne koordynowanie wydajności piezoelektrycznej z temperaturą Curie i realizuje równoczesne polepszenie właściwości piezoelektrycznych i temperatury Curie, co ma wielkie znaczenie dla promowania praktycznego zastosowania wysokotemperaturowej ceramiki piezoelektrycznej
16
Content available remote Synthesis, growth and characterization of NaAl(SO4)·H2O triangular prism single crystal for inorganic NLO application
Sakthi P., Rajasekaran R., Arun A.
Materials Science Poland
|
2019
|
Vol. 37, No. 2
142--148
EN
An inorganic coordination complex of single crystal containing sodium and aluminum (SA) was grown at room temperature by slow evaporation technique. The crystal was characterized using single crystal X-ray diffraction (XRD), FT-IR, UV-Vis, SHG, SEM, EDX and TG/DTA analyses. The size of the grown crystal was around 17 mm × 15 mm × 5 mm. Both optical and SEM photographs confirmed that the crystal is transparent with smooth surface. The XRD data showed that the crystal belongs to the BCC crystal structure. The crystal shows excellent transparency in the entire region of visible light (cut-off value is 339 cm−1 ). The dielectric constant as well as dielectric loss of the sample was calculated by varying frequencies at different temperatures and the presence of low dielectric loss proved that this crystal can be used for the NLO application.
17
Content available remote Influence of Bi on dielectric properties of GaAs1−xBix alloys
Ulutas K., Yakut S., Bozoglu D., Deger D., Arslan M., Erol A.
Materials Science Poland
|
2019
|
Vol. 37, No. 2
244--248
EN
Pure GaAs and GaAs1−xBix alloys with different Bi ratios (1 %, 2.5 %, 3.5 %) fitted with silver contacts were measured with a dielectric spectroscopy device. Dielectric characterization was performed at room temperature in the frequency range of 0.1 Hz to 1 MHz. GaAs exhibits three relaxation regions corresponding to space-charge, dipolar and ionic polarizations in sequence with increasing frequency while GaAs1−xBix samples show only a broad dipolar polarization in the same frequency range. This result proves the filling of the lattice with Bi through making a new bonding reducing the influence of ionic polarization. This finding supports the previous results concerning optical properties of GaAs1−xBix, presented in the literature.
18
Content available remote Dielectric properties of Bi-substituted LDHs synthesized by co-precipitation and sol-gel methods
Sokol Denis, Ivanov Maksim, Salak Andrei N., Grigalaitis Robertas, Banys Juras, Kareiva Aivaras
Materials Science Poland
|
2019
|
Vol. 37, No. 2
190--195
EN
Magnesium-aluminum-bismuth layered double hydroxides (Mg3Al1-xBix; LDHs) were prepared using both coprecipitation and sol-gel methods. For the preparation of Mg/Al/Bi LDH by the co-precipitation method, the appropriate amounts of dissolved starting materials (Al(NO3)3·9H2O, Mg(NO3)2·6H2O and Bi(NO3)3·5H2O) were mixed with a solution of NaHCO3:NaOH. In the sol-gel processing, the precursor Mg–Al–Bi–O gels were synthesized using the same starting materials and ethylene glycol as complexing agent. The mixed-metal oxides obtained by subsequent heating of Mg–Al–Bi–O gels at 650 °C were reconstructed to Mg3Al1-xBix LDHs in water at 80 °C. All the synthesized products were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and dielectric measurements.
19
Content available Investigation into the Dielectric Properties of Polypyrrole Coated Fabrics Composites
Ge Chuanbing, Liu Yuanjun, Qian Xiaoming, Zhao Xiaoming
Fibres & Textiles in Eastern Europe
|
2019
|
Vol. 27, no. 5 (137)
75--81
EN
Flexible polypyrrole coated fabric composites with good dielectric properties were produced using pyrrole as a monomer by in-situ polymerisation on polyester fabric. Initially, the influence of the pyrrole concentration, temperature and time on the dielectric constant of the real and imaginary parts, the loss tangent, and the surface resistance of the composites were investigated. Subsequently, exterior morphologies was analysed. The results show that the pyrrole concentration, the reaction temperature and time had a significant influence on the real and imaginary parts of the dielectric constant, the loss tangent, and the surface resistance of the composites. The polypyrrole composites produced show good performance in terms of dielectric properties and electrical conductivity.In the 0-106 Hz frequency range, the values of the real and imaginary parts of the dielectric constant of the 0.8mol/L group are both at their largest. Moreover, the value of the surface resistance of the 0.8 mol/L group is at its smallest, and the value of the surface resistance of the 0.2 mol/L group is at its largest, which is 12 times the value given by the 0.8mol/L group.Values of the real and imaginary parts of the dielectric constant, and the loss tangent for the experimental group produced by polymerisation at ambient temperature are at their largest, which is superior to the other groups. The value of the surface resistance for the experimental group produced at ambient temperature is at its smallest and the electrical conductivity is at its strongest; the higher the reaction temperature, the larger the value of the resistance. The various dielectric properties of the 150 min group are better than for the other groups.
PL
W pracy wytworzono kompozyty z elastycznych tkanin powlekanych polipirolem. Oceniono właściwości dielektryczne wytworzonych tkanin. Badano wpływ stężenia pirolu, temperatury i czasu na stałą dielektryczną i odporność powierzchni kompozytów. Następnie przeanalizowano morfologię zewnętrzną. Wyniki pokazały, że stężenie pirolu, temperatura i czas reakcji miały znaczący wpływ na stałą dielektryczną i odporność powierzchni kompozytów. Wytworzone kompozyty wykazywały dobrą wydajność pod względem właściwości dielektrycznych i przewodności elektrycznej. W zakresie częstotliwości 0-106 Hz wartości stałej dielektrycznej dla stężenia polipirolu 0,8 mola/l były największe. Wartość rezystancji powierzchniowej dla stężenia polipirolu 0,8 mol/l była najmniejsza, a wartości rezystancji powierzchniowej dla stężenia polipirolu 0,2 mol/l były największe, co stanowiło 12-krotność wartości podanej dla stężenia polipirolu 0,8 mola/l. Dla próbki wytworzonej przez polimeryzację w temperaturze otoczenia wartości stałej dielektrycznej były największe, natomiast wartość rezystancji powierzchniowej była najmniejsza, a przewodność elektryczna najsilniejsza. Stwierdzono, że im wyższa temperatura reakcji, tym większa wartość oporu. Różne właściwości dielektryczne próbki uzyskanej z czasem reakcji 150 min były lepsze od innych grup.
20
Content available remote Structural and dielectric properties of superparamagnetic iron oxide nanoparticles (SPIONs) stabilized by sugar solutions
Kumar D. S., Naidu K. C. B., Rafi M. M., Nazeer K. P., Begam A. A., Kumar G. R.
Materials Science Poland
|
2018
|
Vol. 36, No. 1
123--133
EN
Superparamagnetic iron oxide nanoparticles (SPIONs) have been synthesized using co-precipitation method. Their microstructure and dielectric properties were studied. The sugar solutions like glucose, fructose and sucrose were used as stabilizers to control the size of the SPIONs. The crystal structure and grain size of the particles were determined by X-ray diffraction. The magnetic studies of the samples were carried out using the vibrating sample magnetometer and their surface morphology was studied by HRTEM, FE-SEM and zeta potential. The dielectric properties of glucose-SPIONs (GF), fructose-SPIONs (FF) and sucrose-SPIONs (SF) were investigated in the frequency range of 10 Hz to 5 MHz at selected temperatures. The FF showed a high dielectric constant of 62 at 1 MHz and the dielectric properties of SPIONs were found to have been significantly improved, especially in the low frequency regime according to the Maxwell-Wagner interfacial polarization. The AC conductivity measurements revealed that the electrical conduction depends on both frequency and temperature. Impedance analysis was carried out using Cole-Cole plot and the conduction mechanism of the studied compounds was explained. R and C values were further calculated using RC-circuit.
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