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Nanocomposites graphene/CoFe2O4 and graphene/NiFe2O4 – preparation and characterization

100%
Jędrzejewska A., Sibera D., Pełech R., Jędrzejewski R., Narkiewicz U.
Archives of Metallurgy and Materials
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2019
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vol. 64
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issue 1
2
Content available remote

Effect of Synthesis Parameters of Graphene/Fe₂O₃ Nanocomposites on Their Structural and Electrical Conductivity Properties

100%
Jedrzejewska A., Sibera D., Narkiewicz U., Pełech R., Jedrzejewski R.
Acta Physica Polonica A
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2017
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vol. 132
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issue 4
1424-1429
EN
Due to its fascinating properties such as high surface area, very good electrical and thermal conductivity, excellent mechanical properties, optical and electrochemical properties, graphene may be the ideal material as a substrate of nanocomposites for applications in electronics. Graphene layer can be used as a conductive matrix allowing good contact between crystallites of nanomaterials. Despite pure graphene, its composites with other species can be of interest. In this paper the results of studies on the effect of methods and parameters of synthesis, for obtaining composites graphene/Fe₂O₃ on their structural properties and electrical properties are presented. A series of experiments was conducted using a commercially available graphene (Graphene Nanopowder AO-3) and iron nitrate. The materials were obtained using two pressure methods: pressure synthesis in the autoclave and synthesis in the microwave solvothermal reactor. The syntheses were carried out in a solution of ethanol. The specific surface area, helium density, morphology, phase composition, thermal properties and electric conductivity of the obtained composites were investigated.
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Photoluminescence and Chromaticity Properties of ZnO Nanopowders Made by a Microwave Hydrothermal Method

86%
Wolska E., Sibera D., Witkowski B., Yatsunenko S., Pełech I., Narkiewicz U., Godlewski M.
Acta Physica Polonica A
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2011
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vol. 120
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issue 5
908-910
EN
Four series of ZnO nanopowders obtained by a microwave hydrothermal method are examined. Two different solvents (ethanol and distilled water) and different values of pressure during heating in the reactor were used. The obtained nanopowders show a bright emission covering visible light spectral region, including the band edge emission. Results of scanning electron microscopy, X-ray diffraction, photo- and cathodoluminescence investigations and also CIE1961 chromaticity diagram are presented.
4
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Synthesis and Characterization of ZnO Doped with Fe_{2}O_{3} - Hydrothermal Synthesis and Calcination Process

86%
Sibera D., Jędrzejewski R., Mizeracki J., Presz A., Narkiewicz U., Łojkowski W.
Acta Physica Polonica A
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2009
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vol. 116
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issue S
S-133-S-135
EN
The aim of the present work is to compare two methods of synthesis of nanocrystallline zinc oxide doped with iron oxide. The synthesis was carried out using microwave asssisted hydrothermal synthesis and traditional wet chemistry method followed by calcination. The phase composition of the samples was determined using X-ray diffraction measurements. Depending on the chemical composition of the samples, hexagonal ZnO, and/or cubic ZnFe_{2}O_{4} were identified. The morphology of the received materials was characterized using scanning electron microscopy. Two different structures of agglomerates were observed: a hexagonal structure (corresponding to zinc oxide) and spherical (corresponding to spinel phase). The effect of the iron oxide concentration on specific surface area and density of the samples was determined.
5
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Synthesis by Wet Chemical Method and Characterization of Nanocrystalline ZnO Doped with Fe_2O_3

86%
Narkiewicz U., Sibera D., Kuryliszyn-Kudelska I., Kilański L., Dobrowolski W., Romčević N.
Acta Physica Polonica A
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2008
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vol. 113
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issue 6
1695-1700
EN
Nanocrystalline samples of ZnO doped with Fe_2O_3 were synthetized by wet chemical method. The series of ZnO nanosized samples in the wide range of Fe_2O_3 concentration (from 5 wt.% to 95 wt.%) was prepared by precipitation from nitrate solutions using ammonia. The phase composition of the samples was determined using X-ray diffraction measurements. The phases of hexagonal ZnO, and/or rhombohedric Fe_2O_3, and/or ZnFe_2O_4 were identified. The mean crystalline size of nanocrystals, determined with the use of Scherrer's formula, varied from 8 to 52 nm. The preliminary micro-Raman spectroscopy measurements were performed. The observed features are typical of Fe doped ZnO nanoparticles. The magnetic measurements revealed the presence of different types of magnetic behavior. For samples with high Fe_2O_3 contents (above 70 wt.%) the ferromagnetic ordering was observed at room temperature. For samples with lower Fe_2O_3 contents we observed the phenomenon of superparamagnetism above the blocking temperature.
6
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Magnetic Resonance Study of MnO/ZnO Nanopowders

86%
Guskos N., Zolnierkiewicz G., Typek J., Sibera D., Narkiewicz U., Łojkowski W.
Acta Physica Polonica A
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2011
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vol. 120
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issue 6
1074-1079
EN
Fine particles n(MnO)/-(1-n)ZnO (n = 0.05 to 0.95) were prepared by wet chemistry method. According to X-ray diffraction analysis the obtained samples with n = 0.95, 0.90, 0.80, 0.70, 0.60 contained Mn_3O_4 and ZnMn_2O_4 phases, while samples with n = 0.05, 0.10, 0.20, 0.30, 0.40 and 0.50 contained ZnMnO_3 and ZnO phases. The mean crystalline size of ZnMnO_3 varied from 8 to 13 nm. The magnetic resonance investigations have been carried out at room temperature. Slightly asymmetric, broad and intense magnetic resonance line is recorded for all samples. The magnetic resonance spectra parameters showed marked differences depending on the composition index n. This could be explained by the variation of the magnetic susceptibility and a much slower evolution of spin relaxation, associated with the interaction of crystal field and superexchange interactions. Taking into account the values of magnetic resonance parameters, the investigated samples could be divided into two groups: these with the composition index n<0.50 and those with n>0.50. A detailed discussion of the magnetic properties of different phases in the n(MnO)/-(1-n)ZnO system is presented.
7
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FMR Study of Temperature Dependence of Magnetic Properties of Nanocrystalline 0.90(Fe_2O_3)/0.10ZnO

86%
Guskos N., Glenis S., Zolnierkiewicz G., Typek J., Sibera D., Narkiewicz U.
Acta Physica Polonica A
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2011
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vol. 120
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issue 6
1070-1073
EN
The nanocrystalline mixed system 0.90(Fe_2O_3)/-0.10ZnO has been prepared by coprecipitation and calcination processes. The phase composition of samples was determined by X-ray diffraction. The studied nanocrystalline sample is dominated by phase Fe_2O_3 but very small amounts of ZnO and ZnFe_2O_4 phases were also identified. The ferromagnetic resonance investigations of the obtained sample have been carried out in the temperature range from liquid helium to room temperature. The asymmetrical and very intense magnetic resonance line was recorded at all temperatures. A significant shift of spectra towards lower magnetic fields with decreasing temperature was observed. A very good fitting by two Lorentzian functions has been obtained which suggested the existence of a strong anisotropic magnetic interaction. Some similarities in behaviour of ferromagnetic resonance parameters of the present sample and the 0.95Fe_2O_3Fe2O3/0.05ZnO sample were noticed but the parameters values were essentially different. The gradients Δ H_{r}/Δ T (where H_{r} is the resonance field), the broadening processes of the resonance lines as well as the line amplitudes were changing more intensely changing with temperature in comparison to sample 0.95Fe_2O_3Fe2O3/0.05ZnO. The following values Δ H_{r}/Δ T are obtained: 16.7(1) Gs/K and 20.7(1) Gs/K over the 60 K temperatures where below 40 K is 41.5(1) Gs/K and 56.0(1) Gs/K. The reorientation processes were more active at low temperatures for smaller concentrations of magnetic nanoparticles.
8
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Nanocrystalline ZnO Doped with Fe_2O_3 - Magnetic and Structural Properties

73%
Kuryliszyn-Kudelska I., Hadžić B., Sibera D., Kilanski L., Romčević N., Romčević M., Narkiewicz U., Dobrowolski W.
Acta Physica Polonica A
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2011
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vol. 119
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issue 5
689-691
EN
We have studied the magnetic properties of ZnO nanocrystals doped with Fe_2O_3 in the magnetic dopant range from 5 to 70 wt%. The nanocrystals were synthesized by wet chemical method. The detailed structural characterization was performed by means of X-ray diffraction and micro-Raman spectroscopy measurements. The results of systematic measurements of magnetic AC susceptibility as a function of temperature and frequency are presented. We observed different types of magnetic behavior. For ZnO samples doped with low content of Fe_2O_3, the results of low-field AC susceptibility are satisfactorily explained by superparamagnetic model including inter-particle interactions. With the increase of magnetic Fe_2O_3 content, the spin-glass-like behavior is observed.
9
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Raman Scattering from ZnO(Fe) Nanoparticles

73%
Romčević N., Kostić R., Romčević M., Hadžić B., Kuryliszyn-Kudelska I., Dobrowolski W., Narkiewicz U., Sibera D.
Acta Physica Polonica A
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2008
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vol. 114
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issue 5
1323-1328
EN
Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine composition of the samples (ZnO, Fe₂O₃, ZnFe₂O₄) and the mean crystalline size (8-52 nm). In this paper we report the experimental spectra of the Raman scattering (from 200 to 1600 cm¯¹). Main characteristics of experimental Raman spectrum in 200 to 1600 cm¯¹ spectral region are: sharp peak at 436 cm¯¹ and broad two-phonon structure at ≈ 1150 cm¯¹, typical of ZnO;broad structure below 700 cm¯¹ that has different position and shape in case of ZnFe₂O₄ or Fe₂O₃ nanoparticles.
10
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Low-Frequency Raman Scattering from ZnO(Fe) Nanoparticles

73%
Kostić R., Romčević N., Romčević M., Hadžić B., Rudolf R., Kuryliszyn-Kudelska I., Dobrowolski W., Narkiewicz U., Sibera D.
Acta Physica Polonica A
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2009
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vol. 116
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issue 1
65-67
EN
Nanocrystalline samples of ZnO(Fe) were synthesized by wet chemical method. Samples were characterized by X-ray diffraction to determine the sample composition and the mean crystalline size. Low-frequency Raman modes were measured and assigned according to confined acoustic vibrations of spherical nanoparticles. Frequencies of these vibrational modes were analyzed in elastic continuum aproximation, which considers nanoparticle as homogeneous elastic sphere.
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