Browsing by Author "Kuru, Tugba Sasmaz"

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Citation Count: 12
Dielectric, humidity behavior and conductivity mechanism of Mn_0.2Ni_0.3Zn_0.5Fe₂O₄ ferrite prepared by co-precipitation method
(Springer, 2018) Kuru, Tugba Sasmaz; Şaşmaz Kuru, Tuğba; Bagci, Sadik; Radyoterapi / Radiotherapy
Mn-Ni-Zn ferrite with the chemical formula of Mn0.2Ni0.3Zn0.5Fe2O4 was prepared by co-precipitation method. The X-ray diffraction (XRD) results show that the prepared sample crystallizes in the cubic spinel structure with the space group of Fm3m. The morphological analysis of the sample was investigated by scanning electron microscopy (SEM). The dielectric properties of Mn0.2Ni0.3Zn0.5Fe2O4 ferrite were studied in a frequency range from 20 Hz to 10 MHz and at a temperature range from 293 to 733 K. The dielectric constant decreases with the increasing frequency for all the temperature values chosen. The AC conductivity mechanism was found the small polaron type of conductivity, and in addition to that, the DC conductivity can be explained by Arrhenius type conductivity. According to the dielectric results, relaxation process fits Cole-Cole model. Finally, the effect of the relative humidity upon the impedance of the sample was discussed for a frequency range between 20 Hz and 10 MHz. It is found that the impedance values decrease almost linearly with the increasing % RH (relative humidity) values at low frequencies, while the impedance of the sample is independent of % RH at high frequencies.
Citation Count: 25
Dielectric, magnetic and humidity properties of Mg-Zn-Cr ferrites
(Elsevier Science Sa, 2020) Kuru, Mehmet; Kuru, Tugba Sasmaz; Karaca, Ertugrul; Bagci, Sadik
In this study, Cr3+ substituted Mg0.75Zn0.25CrxFe2-xO4 (x = 0, 0.1, 0.3) (Mg-Zn-Cr) ferrites have been synthesized using chemical co-precipitation method. The crystal structure and phase formation of Mg-Zn-Cr ferrites have been analyzed by X-Ray diffraction (XRD) method. The crystal size (from 15.37 nm to 10.84 nm) and lattice constant (from 8.405 angstrom to 8.384 angstrom) of the crystallized in cubic crystal structure Mg-Zn-Cr samples decreased with Cr3+ contribution. The change in lattice strain determined by Williamson-Hall (W-H) graphs. Morphological and elemental analysis were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. The variations in temperature-dependent dielectric properties of samples between 290 K and 700 K were examined in the range from 20 Hz to 10 MHz. Curie temperature, where maximum dielectric constant is observed, shifted low temperatures with increasing Cr3+ contribution. This peak shift indicates that the materials have a relaxor ferroelectric character in accordance with the literature. Impedance analysis of Mg-Zn-Cr ferrites were investigated using Nyquist curves and relaxation process confirms Cole-Cole model. The magnetic properties of the samples in the range of +/- 5 kOe at 300 K were examined with the help of the Vibrating Sample Magnetometer (VSM). The M - H hysteresis loops of all samples showed the characteristic properties of soft magnetic materials. Finally, the effect of relative humidity (%RH) on the impedance of samples for different frequency values was investigated. (C) 2020 Elsevier B.V. All rights reserved.
Citation Count: 0
Effect of calcination temperature on structural, magnetic, and dielectric properties of Mg_0.75Zn_0.25Al_0.2Fe_1.8O₄ ferrites
(Springer, 2024) Kuru, Tugba Sasmaz; Şaşmaz Kuru, Tuğba; Radyoterapi / Radiotherapy
Based on the desire to improve material properties, the effects of temperature have begun to be investigated. It was found that for nano-sized powder materials, such as ferrites, the structural properties like crystal structure and grain size, as well as many magnetic and electrical properties depending on them, change with the calcination temperature. Considering these changes, the effect of calcination temperature on the structural, magnetic, and electrical properties of MZA ferrites (Mg0.75Zn0.25Al0.2Fe1.8O4) prepared by co-precipitation was investigated in this study. The produced MZA ferrites were calcined at three different temperatures (600, 700, and 800 C-degrees). The X-ray diffraction results showed that the samples exhibited a cubic spinel structure. It was found that the crystal sizes (D_sch) calculated using the Debye-Scherrer equation increased with increasing calcination temperature (22.47, 33.53, and 42.53 nm). From the Williamson-Hall (W-H) plots, crystal sizes were calculated almost same as Debye-Scherrer crystal sizes. The nano-sized particles were examined by scanning electron microscope (SEM). Elemental analysis was performed using EDX. nu(1) and nu(2) absorption bands and O-H and C-H vibrations were detected in the FTIR spectra. Magnetic measurements were carried out at room temperature and in the range of +/- 60 kOe under the applied field. Magnetic results are explained by superparamagnetism. Dielectric measurements were performed at room temperature and a frequency range of 20 Hz to 10 MHz. The dielectric properties can be explained by Maxwell-Wagner theory. Impedance spectroscopy study revealed that the relaxation mechanism is consistent with the Cole-Cole model. In AC conductivity studies at room temperature, it was found that the sample calcined at 600 C-degrees would be suitable for energy storage devices.
Citation Count: 20
The role of the calcium concentration effect on the structural and dielectric properties of mixed Ni-Zn ferrites
(Springer, 2019) Kuru, Mehmet; Şaşmaz Kuru, Tuğba; Bagci, Sadik; Radyoterapi / Radiotherapy
The calcium substituted nickel-zinc ferrites with the formula of CaxNi0.75-xZn0.25Fe2O4 (x=0, 0.25, 0.5 and 0.75) have been prepared by using the chemical co-precipitation method. The X-ray diffraction (XRD) analyses reveal the results that all the samples crystallize in cubic spinel structure and the lattice constants of the samples for x=0, 0.25, 0.50 and 0.75 are found to be 8.334, 8.348, 8.380 and 8.538 angstrom, respectively. The crystallite size of the samples, obtained from Debye Scherrer's equation, varies between 12nm and 27nm. The scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses have been conducted to reveal and determine the morphology and stoichiometry of all the prepared CaxNi0.75-xZn0.25Fe2O4 ferrite samples. The SEM images show that the partical sizes for all the samples are at nano size in accordance with the XRD results and EDX results confirm the contents of the produced samples. The dielectric and impedance properties of the prepared ferrite samples have been investigated in the frequency range from 20Hz to 10MHz and in the temperature range from 350 to 700K. The real and imaginary parts of dielectric constant, tan , AC and DC conductivity values decrease with increasing calcium content (except x=0). Contrary to this behavior, real and imaginary parts of impedance increase with increasing calcium content. The general AC conductivity behavior of all samples is like semiconductor behavior. The conductivity mechanism of the sample with x=0 is explained by the mechanism of correlated barrier hopping (CBH), while it has turned into overlapping large polaron tunneling (OLPT) mechanism for all other samples. From the relaxation time graphs obtained from the impedance data, activation energies of the grain and grain boundaries are obtained. The Nyquist plots are also presented in the temperature range of 350-700K to determine the conductivity mechanism of the prepared samples and all the plots show only one semi-circle, which means that the dominant transmission comes from the grain boundaries.
Citation Count: 4
Room temperature structural, dielectric, and conductivity properties of Al_xCd_1-xFe₂O₄ ferrites
(Springer, 2020) Kuru, Tugba Sasmaz; Şaşmaz Kuru, Tuğba; Radyoterapi / Radiotherapy
The purpose of this study is to investigate dielectric and conduction mechanisms in accordance with composition at room temperature. In this study, AlxCd1-xFe2O4 ferrites with different stoichiometric rates (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared through co-precipitation method. The precipitated powder was sintered at 800 degrees C for 8 h to form the pure spinel ferrite nanoparticle. The formation of the cubic spinel phase has been demonstrated by X-ray diffraction analysis. The resulting powder was shown to be nanosized. Experiments were performed at room temperature in the frequency range of 20 Hz to 10 MHz. Frequency-dependent dielectric permittivity and dielectric loss for all examined samples exhibit the dielectric relaxation phenomenon explained by the Maxwell-Wagner polarization. Dielectric constant, AC conductivity, and dielectric loss decreased with increasing frequency. Dielectric constant, dielectric loss, and AC conductivity decreased along with increasing stoichiometric ratio x = 0 to 0.5. However, deviations in the intermediate values were observed, and the values of 0.2 were between 0 and 0.1 and the values of 0.3 were between 0.4 and 0.5. The impedance analysis explained the role of grains and grain boundaries within prepared samples. As a result, it was found that the relaxation process was compatible with the Cole-Cole model.
Citation Count: 25
Structural, dielectric and humidity properties of Al-Ni-Zn ferrite prepared by co-precipitation method
(Elsevier Science Sa, 2018) Kuru, Tugba Sasmaz; Şaşmaz Kuru, Tuğba; Bagci, Sadik; Radyoterapi / Radiotherapy
Al0,2Ni0,3Zn0,5Fe2O4 ferrite nanoparticles have been synthesized by chemical co-precipitation method and structural characterization has been analyzed using X-Ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis indicates that Al0,2Ni0,3Zn0,5Fe2O4 ferrite nanoparticles crystallize in the cubic spinel phase. To determine the electrical properties of the sample, the real and imaginary parts of the dielectric constant have been investigated to a frequency range from 20 Hz to 10 MHz for 31 test frequencies. These measurements have been also repeated for different temperatures. The impedance analysis of the sample was carried out using Nyquist curves. The variation of the conductivity of the sample is also shown for the 31 test frequencies and the different temperature values in the range between 293 K and 733 K. The DC conductivity of the Al0,2Ni0,3Zn0,5Fe2O4 as a function of temperature is also presented and the measurements confirm that the sample exhibits semiconductor behavior in accordance with the literature. Finally, the relative humidity, frequency and impedance map of the sample has been investigated in detail. (c) 2018 Elsevier B.V. All rights reserved.
Citation Count: 10
Structural, optical, and dielectric properties of Cu, Ni-doped Zn ferrites
(Springer, 2019) Kuru, Tugba Sasmaz; Kuru, Mehmet
Ferrite nanocomposites with the composition Cu0.5Zn0.5Fe2O4 and Ni0.5Zn0.5Fe2O4 were prepared by co-precipitation method. The effect of dopant to spinel ferrite ZnFe2O4 on the structural, morphological, optical, and dielectric properties of the as-prepared Cu-Zn and Ni-Zn ferrites were investigated. The structural, elemental, and optical properties conducted by using X-ray diffraction (XRD) technique with Cu/K alpha radiation, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Raman spectroscopy, and UV-Vis reflectance spectroscopy. For the electrical properties of the Cu-Zn and Ni-Zn ferrites, a real part of the dielectric constant and AC conductivity have been investigated with a frequency range of 20 Hz to 10 MHz at different temperature for each sample. The substitutions of Cu and Ni into the ZnFe2O4 nanocomposites crystal size calculated 20.36 nm for Cu-Zn ferrite and 10.95 nm for Ni-Zn ferrite. Also, the energy band gap of Cu-Zn ferrite is 2.6 eV and Ni-Zn ferrite is 2.83 eV. These results show that the energy band gap is increased when the crystal size is reduced by the substitution of Ni into the Zn ferrite. The dielectric constant and AC conductivity of Cu-Zn ferrite is bigger than the Ni-Zn ferrite at low frequencies. This situation is related to the structural parameters. Also, the AC conductivity increases with an increasing frequency and temperature.
Citation Count: 0
Synthesis and electrical properties of 2,9(10),16(17),23(24){4-[bis[2-(hydroxy)ethyl]amino}benzyloxy-phthalocyaninatozinc(II)
(Elsevier, 2021) Cenikli Başeren, Şükran; Kuru, Tugba Sasmaz; Gul, Ahmet; Patoloji Laboratuvar Teknikleri / Pathology Laboratory Techniques
A novel zinc phthalocyanine with four 4-bis(hydroxyethylamino)benzyloxy groups was synthesized and characterized by using IR, H-1 and C-13 NMR and UV-VIS spectral data. Also, some physical analyses were carried out on this new zinc phthalocyanine. Conductivity, dielectric and impedance properties of the sample were investigated in the temperature range of 300-525 K and the frequency range of 100-10 MHz. It has been found that DC conductivity can be explained by Arrhenius type conductivity and the transition is from extrinsic conduction to intrinsic conduction. AC conductivity exhibits an almost linear behavior with frequency explained by the quantum mechanical tunneling (QMT) model. The dielectric constant decreased with increasing frequency, but instead increased with increasing temperature. This is an indication that dielectric dipoles are thermally active. From the results obtained by impedance spectroscopy, it was found that the relaxation process is a Cole-Cole model. (C) 2021 Elsevier B.V. All rights reserved.
Citation Count: 11
Synthesis and investigation of structural, dielectric, impedance, conductivity and humidity sensing properties of Cr³⁺-substituted Mg-Zn ferrite nanoparticle
(Springer Heidelberg, 2020) Kuru, Tugba Sasmaz; Şaşmaz Kuru, Tuğba; Radyoterapi / Radiotherapy
In this study, structural, dielectric, impedance and humidity properties of Cr3+-doped Mg-Zn ferrite, produced by co-precipitation method, have been investigated. Structural, morphological and compositional analyses were studied by XRD, SEM and EDX, respectively. The X-ray diffraction result shows that Mg0.75Zn0.25Cr0.2Fe1.8O4 crystallizes in the cubic spinel structure with the space group of Fd3m. The lattice constant and crystal size of the sample were calculated as 8.4046 angstrom and 11.29 nm. The dielectric and impedance properties were investigated in the frequency range between 20 and 10 MHz and in the temperature range from 290 to 710 K. The dielectric results are supported by Maxwell-Wagner polarization principles. Relaxation mechanism of the sample is explained by Nyquist graph. According to the impedance results, relaxation process is compatible with Cole-Cole model. The conductivity mechanism of the sample is explained by the mechanism of correlated barrier hopping (CBH) model. Finally, the humidity sensing properties of sample were investigated by impedance measurements in the range of 25-90 RH % at room temperature.
Citation Count: 1
Temperature- and frequency-dependent electrical characterization with humidity properties in MZC nanoferrites
(Springer, 2022) Kuru, Mehmet; Şaşmaz Kuru, Tuğba; Radyoterapi / Radiotherapy
In this study, Mg0.75Zn0.25CrxFe2-xO4 (x = 0.4, 0.5) (MZC) nanoferrites were prepared by chemical co-precipitation. The crystal properties, surface morphology and magnetic properties of the MZC nanoferrites were investigated by XRD, FT-IR, SEM and VSM. The dielectric, impedance, and conductivity properties of MZC nanoferrites were studied between room temperature and 710 K and in the frequency range from 20 Hz to 10 MHz. The complex impedance behavior of the samples is determined using Nyquist plots. The AC conductivity mechanism is explained by the quantum mechanical tunneling (QMT) model, while the DC conductivity mechanism is expressed by the Verwey De Bour mechanism. According to the modulus results, the relaxation process in the high frequency region is a non-Debye relaxation. In addition, the humidity sensing properties and the influence of relative humidity (% RH) on the impedance of the samples in the range of 20-90 RH % at room temperature were investigated.