Yazar "Almessiere, Munirah Abdullah" seçeneğine göre listele

Listeleniyor 1 - 20 / 29
  • [ X ]
    Öğe
    AC susceptibility and hyperfine interactions of Mg-Ca ions co-substituted BaFe 12 O 19 nanohexaferrites
    (Elsevier Ltd, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Ali, Sadaqat S.; Baykal, Abdulhadi; Ercan, İsmail
    Magnesium and calcium co-substituted Ba M-type nanohexaferrite (NHFs) is fabricated via sol-gel auto-combustion technique. The phase formation was proved by XRD powder pattern, FESEM and HR-TEM. Magnetic properties of Ba 1-2x Ca x Mg x Fe 12 O 19 (x ? 0.1) NHFs investigated by Mossbauer Spectroscopy. The variations in line width, quadrupole splitting, isomer shift, the cation distribution of Ca 2+ and Mg 2+ ions and hyperfine magnetic field values were estimated. The AC magnetic susceptibility and ZFC-FC measurements were also performed for the Ba 1-2x Ca x Mg x Fe 12 O 19 (x = 0.02 and 0.08) NHFs. The M FC -M ZFC results do not show blocking temperature peak, indicating the ferrimagnetic (FM) behavior of prepared products. Different models including Neel-Arhenius (N-A), Vogel-Fulcher (V-F) and critical slowing down (CSD) were tested to evaluate the AC-magnetic susceptibility behaviors. It is demonstrated that the magnetic interactions are important for x = 0.02 NHFs. © 2019
  • [ X ]
    Öğe
    AC susceptibility and hyperfine interactions of vanadium substituted barium nanohexaferrites
    (Elsevier Ltd, 2018) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; El Sayed, H. S.; Baykal, Abdulhadi
    Vanadium ions substituted BaFe12O19 nanohexaferrites, BaFe12-xVxO19 (0.0??x???0.1), were produced through the sol-gel auto-combustion route. The structure, morphology and the elemental compositions of various products were examined using X–ray powder diffraction, scanning electron microscopy coupled with EDX and EDS elemental mapping. These techniques confirmed the formation of the desired Ba-nanohexaferrite phases. The crystallites size was found to be 55–58?nm range for all products. The magnetic properties of BaFe12-xVxO19 nanohexaferrites were investigated by Mossbauer spectroscopy, ZFC-FC magnetizations and AC susceptibility. The evolutions in the values of hyperfine magnetic field, isomer shift, quadrupole splitting, and line width were deduced via Mossbauer analysis. The experiments of ZFC and FC magnetizations indicated that no blocking temperature is observed in the temperature interval 2–400?K, which signals the typical ferromagnetic (FM) behavior for the produced nanohexaferrites. A super-spin glass like behavior is noticed at lower temperatures. The experiments AC susceptibility confirmed that the strength of magnetic interactions is enhanced for lower content of V3+ (x?=?0.02). For higher amount of V3+, the magnetic interactions are weakened. The obtained results are mainly accredited to the substitutions of Fe3+ ions by V3+ ions.
  • [ X ]
    Öğe
    AC susceptibility and Mossbauer study of Ce3+ ion substituted SrFe12O19 nanohexaferrites
    (Elsevier Ltd, 2018) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; El Sayed, H. S.; Baykal, Abdulhadi
    Ce3+ ion substituted SrFe12O19, SrFe12-xCexO19 (0.0???x???0.5), nanohexaferrites were fabricated by citrate sol-gel combustion approach. X–ray diffractometry (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscope (EDX), EDX Elemental mapping, Fourier transform infrared spectroscopy (FT-IR) were used to study the structure and morphology of the samples. AC magnetic susceptibility and 57Fe Mossbauer spectroscopy have been operated to examine the hyperfine structure, static and dynamic magnetic properties. The values of variations in line width, quadrupole splitting, hyperfine magnetic field, and isomer shift have been estimated. The impact of Ce-ion substitution on AC magnetic susceptibility properties of Sr-hexaferrite were explored. The AC-susceptibility measurements reveal the frequency dependence of the magnetic responses, indicating strong magnetic interactions among the nanoparticles of the various products. In addition, it is determined that the magnetic interaction between the nanoparticles is weakened in the substituted products, due to the substitution of Fe3+ ions by Ce3+ ions.
  • [ X ]
    Öğe
    Co-substitution of zirconium and neodymium on hyperfine interactions and AC susceptibility of SrFe12O19 nanohexaferrites
    (Chinese Society of Rare Earths, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Baykal, Abdulhadi
    This study presents the influence of Zn and Nd co-substitution on structure, morphology, AC suscepti-bility and ZFC-FC magnetizations of Sr nanohexaferrites (NHFs), SrFe12x?Zn;Nd?xO19(0.0 x 1.0),which was produced by sol-gel approach. XRD powder patterns, scanning electron microscopy (SEM) andhigh-resolution transmission electron spectroscopy (HR-TEM) approve the synthesis of Sr M-type hex-aferrite. Mossbauer spectra show that Zn2?ions occupy 2b and 4f1sites while Nd3?ions locate at 2a,4f2and 12ksites. The magnetic properties of the produced Sr-NHFs were investigated also by ZFC-FCmagnetizations and AC susceptibility. According to theMFC-MZFCresults (between 2 and 400 K), noblocking temperature was detected which indicates the ferromagnetic (FM) behavior of NHFs. At lowertemperatures, a super-spin glass like behavior is discerned. The AC susceptibility indicates that themagnetic interactions are improved due to the inclusion of low content (x¼0.1) of Nd3?and Zn2?ionsinto the Sr-NHFs. However, with further increasing the Nd3?and Zn2?contents (x¼0.9), the magneticinteractions are weakened.
  • [ X ]
    Öğe
    Correlation between chemical composition, electrical, magnetic and microwave properties in Dy-substituted Ni-Cu-Zn ferrites
    (Elsevier, 2021) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Demir Korkmaz, Ayşe; Trukhanov, Sergei V.; Güner, Sadık; Baykal, Abdulhadi
    Dy3+ ion-substituted nanoferrites Ni0.4Cu0.2Zn0.4Fe2_ xDyxO4 (x <= 0.04) were produced via sol-gel method. Correlation between chemical composition, crystal structure, electrical, magnetic and microwave properties was investigated. All samples were characterized by single-phase state. It was observed that the increase of the Dy content leads to a decrease in the average crystallite size. The bandgap (Eg) was deduced to be between 1.83 and 1.86 eV. The measurements of magnetization versus applied magnetic field (M-H) and magnetization versus temperature (M-T) were investigated by vibrating sample magnetometer (VSM). Magnetic measurements revealed superparamagnetic character at room temperature. The magnetization was increased initially with doping Dy3+ in the ratio of x = 0.01 compering to the un-doped sample and thereafter dropped as Dy3+ ions content further increases. Microwave properties were discussed in terms of electromagnetic absorption in the frequency range 1-20 GHz. The occurrences of the intensive electromagnetic absorption in the frequency ranged from 1.6 to 2.7 GHz were observed. The changes in the amplitude-frequency characteristics correlated well with the level of chemical substitution (x) with Dy ions concentration.
  • [ X ]
    Öğe
    Effect of annealing temperature on magnetic and mössbauer properties of ZnFe2O4 nanoparticles by sol-gel approach
    (Springer New York LLC, 2018) Amir, Md.; Güngüneş, Hakan; Baykal, Abdulhadi; Almessiere, Munirah Abdullah; Sözeri, Hüseyin; Ercan, İsmail; Sertkol, Murat; Asiri, Sarah Mousa; Manikandan, A.
    In this study, spinel ZnFe 2 O 4 nanoparticles (NPs) were synthesized by citrate sol-gel route using nickel nitrates, ferric nitrates and citric acid by annealing at 900, 1000, and 1100 ? C. We reported the structural and magnetic properties (including Mössbauer analysis) for anisotropy ZnFe 2 O 4 NPs annealed at different temperatures. Fourier transform infrared (FT-IR) and X-ray powder diffraction (XRD) were utilized to analyze the structural properties of magnetic nanoparticles (MNPs). Morphological features of resultant MNPs were examined by scanning electron microscopy (SEM). The observed XRD results displayed that the crystallite size increased from 38.60 to 49.28 nm with increasing the annealing temperature in a distinct linear trend. The enhancement of saturation magnetization of the uniaxial ZnFe 2 O 4 NPs was studied and varied from 1.28 to 1.66 emu/g as the annealing temperature increases. The Mössbauer spectra results show that ZnFe 2 O 4 ferrites were paramagnetic in nature at room temperature (RT). © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
  • Küçük Resim
    Öğe
    Effects of Ce-Dy rare earths co-doping on various features of Ni-Co spinel ferrite microspheres prepared via hydrothermal approach
    (Elsevier, 2021) Almessiere, Munirah Abdullah; Ünal, Bayram; Slimani, Yassine; Güngüneş, Hakan; Toprak, Muhammet S.; Tashkandi, Nabiha; Manikandan, Ayyar
    The effects of Ce-Dy co-doping on the crystal structure, optical, dielectric, magnetic properties, and hyperfine interactions of Ni-Co spinel ferrite microspheres synthesized hydrothermally have been studied. A series of ferrites with the general formula Ni0.5-Co0.5CexDyxFe2-2xO4 were synthesized with x values ranging from 0.00 to 0.10. The phase, crystallinity, and morphology of ferrite microspheres were analyzed by X-ray powder diffractometry (XRD), scanning and transmission electron microscopes (SEM and TEM), respectively. The structural analyses of the synthesized ferrite microspheres confirmed their high purity and cubic crystalline phase. The Diffuse reflectance spectroscopic (DRS) measurements were presented to calculate direct optical energy band gaps (E-g) and is found in the range 1.63 eV - 1.84 eV. Fe-57 Mossbauer spectroscopy showed that the hyperfine magnetic field of tetrahedral (A) and octahedral (B) sites decreased with the substitution of Dy3+-Ce3+ ions that preferrentially occupy the B site. The impact of the rare-earth content (x) on the magnetic features of the prepared NiCo ferrite microspheres was investigated by analyzing M-H loops, which showed soft ferrimagnetism. The magnetic features illustrate a great impact of the incorporation of Ce3+-Dy3+ ions within the NiCo ferrite structure. The saturation magnetization (M-s), remanence (M-r), and coercivity (H-c) increased gradually with increasing Ce-Dy content. At x = 0.04, M-s, M-r, and H-c attain maximum values of about 31.2 emu/g, 11.5 emu/g, and 512.4 Oe, respectively. The Bohr magneton (n(B)) and magneto-crystalline anisotropy constant (K-eff) were also determined and evaluated with correlation to other magnetic parameters. Further increase in Ce3+-Dy3+ content (i.e., x >= 0.06) was found to decrease M-s, M-r, and H-c values. The variations in magnetic parameters (M-s, M-r, and H-c) were largely caused by the surface spins effect, the variations in crystallite/particle size, the distribution of magnetic ions into the different sublattices, the evolutions of magneto-crystalline anisotropy, and the variations in the magnetic moment (n(B)). The squareness ratios were found to be lower than the predicted theoretical value of 0.5 for various samples, indicating that the prepared Ce-Dy substituted NiCo ferrite microspheres are composed of NPs with single-magnetic domain (SMD). Temperature and frequency-dependent electrical and dielectric measurements have been done to estimate the ac/dc conductivity, dielectric constant, and tangent loss values for all the samples. The ac conductivity measurements confirmed the power-law rules, largely dependent on Ce-Dy content. Impedance analysis stated that the conduction mechanisms in all samples are mainly due to the grains-grain boundaries. The dielectric constant of NiCo ferrite microspheres give rise to normal dielectric distribution, with the frequency depending strongly on the Ce-Dy content. The observed variation in tangential loss with frequency can be attributed to the conduction mechanism in ferrites, like Koop's phenomenological model. (C) 2021 The Author(s). Published by Elsevier B.V.
  • [ X ]
    Öğe
    Exploration of catalytic and cytotoxicity activities of CaxMgxNi1-2xFe2O4 nanoparticles
    (Elsevier Science Sa, 2019) Nawaz, Muhammad; Almessiere, Munirah Abdullah; Almofty, Sarah; Dönmez Güngüneş, Çiğdem; Slimani, Yassine; Baykal, Abdulhadi
    The CaxMgxNi1-2xFe2O4 (x <= 0.05) nanoparticles (NPs) have been synthesized hydrothermally. The XRD analyses confirmed the purity of all products and their spherical morphology and compositions were explained by SEM, TEM, EDX and Elemental mapping analyses. Results confirmed the composition of CaxMgxNi1-2xFe2O4. The surface area of them was determined by BET analysis. Results indicated that when x is increased surface area of CaxMgxNi1-2xFe2O4 is decreased as compare with x = 0.0, however, at high composition (x = 0.05), surface area is increased. Catalytic activity of CaxMgxNi1-2xFe2O4 (x <= 0.05) NPs was studied for the reduction of 4-nitrophenol as a model compound. Reaction was monitored by UV-spectrophotometer at room temperature and at different times. Among different compositions of CaxMgxNi1-2xFe2O4, it was noticed that x = 0.04 exhibited more activity for the reduction of 4-nitrophenol and x = 0.03 was observed least active. Results suggested that CaxMgxNi1-2xFe2O4 could be useful material for catalytic applications. Cytotoxicity activity of CaxMgxNi1-2xFe2O4 (x <= 0.05) NPs against HCT116 (Human colon cancer cell line) cell line and MCF-7 (breast cancer cell line) was evaluated by using MTT assay. It was observed that CaxMgxNi1-2xFe2O4 (x <= 0.05) NPs exhibited less cytotoxicity. Due to less cytotoxicity, CaxMgxNi1-2xFe2O4 may also be useful in the field of biomedical applications.
  • [ X ]
    Öğe
    Hydrothermal synthesis of CoyZnyMn1-2yFe2O4 nanoferrites: Magneto-optical investigation
    (Elsevier Ltd, 2018) Asiri, Sarah Mousa; Sertkol, Murat; Güner, Sadık; Güngüneş, Hakan; Mujasam Batoo, Khalid; Saleh, Tawfik A.; Sözeri, Hüseyin; Almessiere, Munirah Abdullah; Manikandan, A.; Baykal, Abdulhadi
    Manganese ferrites nanoparticles (NPs) substituted with both Co2+ and Zn2+ simultaneously (CoyZnyMn1-2yFe2O4 NPs for y=0.0 to 0.5), have been produced by hydrothermal approach. The substitution with both Co2+ and Zn2+ ions on the structure, spectroscopic and magneto-optical properties of nanocrystalline MnFe2O4 spinel ferrites have been analyzed in detail. The formation of spinel phase and structural changes induced by Co2+ and Zn2+ ions substitutions were confirmed by X-ray diffraction studies. Rietveld refinement revealed the cubic spinel phase for all products (minor amount of Fe2O3). Lattice constant and crystallite size were found to decrease from 8.478 to 8.370 Å and from 14.68 to 8.22 nm, respectively with increasing substitution of Co2+ and Zn2+ ions. HR-SEM and HR-TEM micrographs revealed the high homogeneity cubic structure of samples. The hyperfine magnetic field values for all products after Mn2+, Zn2+ and Co2+ ions substitution were determined by Mössbauer analysis. The estimated optical Eg (Energy band gap) values are in the range of 1.41–1.54 eV for the samples. The smaller Eg values are mainly attributed to greater particle size and decreasing quantum confinement effect. © 2017 Elsevier Ltd and Techna Group S.r.l.
  • [ X ]
    Öğe
    Impact of Gd substitution on the structure, hyperfine interactions, and magnetic properties of Sr hexaferrites
    (Elsevier Sci Ltd, 2021) Almessiere, Munirah Abdullah; Slimani, Yassine; Sertkol, Mehriye; Güngüneş, Hakan; Wudil, Yakubu Sani; Demir Korkmaz, Ayşe; Baykal, Abdulhadi
    Gd3+-substituted nano-sized Sr-hexaferrite, SrGd(x)Fe(12-x)O19 (0.00 <= x <= 0.05) NHFs (SrGd NHFs), were fabricated by a one-pot sol-gel combustion approach assisted by citric acid. The crystal structures, surface morphologies, magnetic properties, and hyperfine interactions of the calcined samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), high-resolution TEM (HR-TEM), vibrating sample magnetometry (VSM), and Mossbauer spectrometry. The oxidation states and chemical compositions of the NHFs were evaluated using XPS. The single-phase crystalline structures of all products were confirmed by XRD analysis. The average crystallite sizes determined from the peaks of the highest intensity using the Scherrer equation were between 38 and 50 nm. Using 57Fe Mossbauer spectroscopy data, the quadrupole splitting, hyperfine magnetic field, isomer shift, and line width variation of the products were determined. The Mossbauer spectra showed that octahedral (O-h) 12k and 2a sites were preferentially occupied by Gd3+ ions. The Gd3+ content was found to have no influence on the electron density around the Fe3+ ions at any crystallographic site. The magnetization (M) versus magnetic field (H) data were collected at room (300 K) and ultra-low (10 K) temperatures. Neither the zero-field cooling (ZFC) nor field cooling (FC) mode plots of magnetization vs. temperature revealed any blocking temperature peaks. Both the M H curves and FC-ZFC magnetization revealed ferrimagnetic behavior of the products. Furthermore, the FC-ZFC magnetization exhibited super-spin glass behavior at low temperatures. Reductions in the coercive field (H-c), saturation magnetization (M-s), and remanence (M-r) magnetization were achieved with Gd substitution of up to 0.03 into the hexaferrite system; however, with further increase in Gd content, these values started to increase. The calculated squareness ratio (M-r/M-s) revealed that all of the NHF samples were composed of single magnetic domain particles with uniaxial anisotropy.
  • [ X ]
    Öğe
    Impact of La3+ and Y3+ ion substitutions on structural, magnetic and microwave properties of Ni0.3Cu0.3Zn0.4Fe2O4 nanospinel ferrites synthesized via sonochemical route
    (Royal Soc Chemistry, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Demir Korkmaz, Ayşe; Baykal, Abdulhadi; Güngüneş, Hakan; Sözeri, Hüseyin; Manikandan, Ayyar
    In the current study, Ni0.4Cu0.2Zn0.4LaxYxFe2-xO4 (x = 0.00 - 0.10) nanospinel ferrites (NSFs) were fabricated via an ultrasonic irradiation route. The creation of single phase of spinel nanoferrites (NSFs) was investigated by X-ray powder diffractometry (XRD) and selected area diffraction pattern (SAED). The cubic morphology of all samples was confirmed by scanning and transmission electron microscopies (SEM and TEM) respectively. The UV-Vis investigations provided the direct optical energy band gap values in a narrow photon energy interval of 1.87-1.92 eV. The Fe-57 Mossbauer spectroscopy analysis explained that the hyperfine magnetic fields of Octahedral (Oh) and Tetrahedral (Td) sites decreased with substitution. The paramagnetic properties of NPs decrease with increase of content of doped ions. Investigations of magnetic properties reveal a superparamagnetic nature at 300 K and soft ferromagnetic trait at 10 K. The M-s (saturation magnetization) and M-r (remanence) decrease and the H-c (coercivity) increases slightly with La3+ and Y3+ substitution. The observed magnetic traits are deeply discussed in relation with the morphology, structure, magnetic moments and cation distributions. The microwave characterization of the prepared NSFs showed that, dissipation (i.e., absorption) of incoming microwave energy occurs at a single frequency, for each sample, lying between 7 and 10.5 GHz. The reflection losses (RL) at these frequencies range from -30 to -40 dB and the mechanism of which is explained in the framework of dipolar relaxation and spin rotation. The best microwave properties were obtained with a LaY concentration of x = 0.08 having an RL of -40 dB @ 10.5 GHz and an absorption bandwidth of 8.4 GHz @ -10 dB. With these high values of RL and absorbing bandwidth, LaY doped NiCuZn NSF products would be promising candidates for radar absorbing materials in the X-band.
  • Küçük Resim
    Öğe
    Influence of Dy3+ Ions on the Microstructures and Magnetic, Electrical, and Microwave Properties of [Ni0.4Cu0.2Zn0.4](Fe2-xDyx)O-4 (0.00 <= x <= 0.04) Spinel Ferrites
    (Amer Chemical Soc, 2021) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Demir Korkmaz, Ayşe; Zubar, Tatiana; Trukhanov, Sergei; Baykal, Abdulhadi
    [Ni0.4Cu0.2Zn0.4](Fe2-xDyx)O-4 spinel ferrite nanoparticles with different Dy3+ concentrations (0.00 <= x <= 0.04) were prepared by a citrate sol-gel auto-combustion technique. A strong correlation among Dy concentration, structural parameters, and magnetic, electrical, and microwave properties was established. An increase in the Dy3+ concentration is the reason for a rise in the crystal structure parameters (due to different ionic radii of Fe and Dy ions) and a slight increase in the average particle size with a minor reduction in the specific surface area. It was observed that Dy3+ ions prefer to occupy the octahedral B site due to their large ionic radius (0.91 A). The explanation of the electrical and magnetic properties was given in terms of the features of Dy3+-O2--Fe3+ dysprosium-oxygen-iron indirect exchange. The occurrence of the intensive changes in amplitude-frequency characteristics was observed from 1.6 to 2.7 GHz. The explanation of electromagnetic absorption was given in terms of the peculiarities of the microstructure (resonance of domain boundaries). The results open perspectives in the utilization of [Ni0.4Cu0.2Zn0.4](Fe2-xDyx)O-4 spinel ferrite nanoparticles as functional materials for targeted drug delivery and hyperthermia applications.
  • [ X ]
    Öğe
    Investigation of the crystal/magnetic structure, magnetic and optical properties of SrYxNbxFe12-2xO19 (x <= 0.05) hexaferrites
    (Iop Publishing Ltd, 2020) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Nawaz, Muhammad; Alahmari, Firas S.; Manikandan, Ayyar; Baykal, Abdulhadi
    Series of Sr hexaferrites (HFs) co-substituted with Nb3+ and Y3+ ions (SrYxNbxFe12-2xO19 (x <= 0.05) were prepared via sol-gel combustion method. In addition to their optical, low temperature, magnetic properties and hyperfine interactions were investigated in detail. X-ray diffraction (XRD) patterns were considered proving both the formation and pureness of products. Mossbauer analysis indicated that the hyperfine field on iron nuclei at all sites decrease with substitution of Y3+-Nb3+ ions into Sr-hexaferrite as a result of changing the magnetic Fe3+ (5 mu(B)) ions by nonmagnetic Y3+ and Nb3+ ions. This leads to decreasing of the magnetic super exchange interaction between the ions. Measurements of AC susceptibility and ZFC-FC magnetizations implemented in a range from room temperature (RT) down to around 2 K. The analysis of M-FC-M-ZFC data proves the ferrimagnetic performance of different prepared HFs in the whole range of 2-325 K and a super-spin glass-like behavior was identified at minimal temperatures. The investigation of AC susceptibility revealed a weakening in the magnetic exchange interactions with the rise in the Nb3+ and Y3+ ions ratios.
  • Küçük Resim
    Öğe
    Investigation of the effects of Tm 3+ on the structural, microstructural, optical, and magnetic properties of Sr hexaferrites
    (Elsevier B.V., 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Manikandan, Ayyar; Baykal, Abdulhadi
    SrTm x Fe 12?x O 4 (0.00 ? x ? 0.10) hexaferrites (HFs) are produced successfully using a sol–gel approach. The structural, optical, and magnetic properties are investigated. The hexagonal phase is confirmed for all the products. The magnetization is measured with respect to the applied magnetic field, M(H). The magnetic parameters including saturation magnetization M s , remanence M r , squareness ratio (SQR = M r /M s ), coercivity H c , and magnetic moment n B are deduced at room (300 K; RT) and low (10 K) temperatures. It is shown that the ferrimagnetic nature and Tm 3+ substitutions lead to decreases in the magnetization and coercivity magnitudes. The results on magnetic properties are investigated extensively with respect to the structural and microstructural properties. The SQR values indicate the formation of a single magnetic domain for the x = 0.0 sample and a multi-magnetic domain structure for the Tm 3+ -substituted Sr HFs (x ? 0.02). The obtained H c values suggest that the produced HFs are promising candidates for potential magnetic recording applications. © 2019 The Authors
  • Küçük Resim
    Öğe
    Magnetic Attributes of NiFe2O4 Nanoparticles: Influence of Dysprosium Ions (Dy3+) Substitution
    (Mdpi, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Ali, Sadaqat; Manikandan, Ayyar; Ercan, İsmail; Trukhanov, Alex V.
    This paper reports the influence of dysprosium ion (Dy3+) substitution on the structural and magnetic properties of NiDyxFe2-xO4 (0.0 <= x <= 0.1) nanoparticles (NPs) prepared using a hydrothermal method. The structure and morphology of the as-synthesized NPs were characterized via X-ray diffraction (XRD), scanning and transmission electron microscope (SEM, and TEM) analyses. Fe-57 Mossbauer spectra were recorded to determine the Dy3+ content dependent variation in the line width, isomer shift, quadrupole splitting, and hyperfine magnetic fields. Furthermore, the magnetic properties of the prepared NPs were also investigated by zero-field cooled (ZFC) and field cooled (FC) magnetizations and AC susceptibility measurements. The M-ZFC (T) results showed a blocking temperature (T-B). Below T-B, the products behave as ferromagnetic (FM) and act superparamagnetic (SPM) above T-B. The M-FC (T) curves indicated the existence of super-spin glass (SSG) behavior below T-s (spin-glass freezing temperature). The AC susceptibility measurements confirmed the existence of the two transition temperatures (i.e., T-B and T-s). Numerous models, e.g., Neel-Arrhenius (N-A), Vogel-Fulcher (V-F), and critical slowing down (CSD), were used to investigate the dynamics of the systems. It was found that the Dy substitution enhanced the magnetic interactions.
  • Küçük Resim
    Öğe
    Magnetic properties, anticancer and antibacterial effectiveness of sonochemically produced Ce3+/Dy3+ co-activated Mn-Zn nanospinel ferrites
    (Elsevier, 2020) Almessiere, Munirah Abdullah; Slimani, Yassine; Rehman, Sümbül; Khan, Firdos Alam; Dönmez Güngüneş, Çiğdem; Güner, Sadık; Baykal, Abdulhadi
    Some new types of Ce3+ and Dy3+ co-doped manganese-zinc nanospinel ferrites (CDMZNSFs) of the form (Mn0.5Zn0.5)[Fe2-2xCexDyx]O-4 (with 0.0 <= x <= 0.1) were sonochemically produced and characterized. The structure, morphology, optical and magnetic properties of these NSFs were determined as a function of co-dopant (Ce3+ and Dy3+) contents. The direct optical band gap energies of the studied NSFs were ranged from 1.54 to 1.85 eV. The measurements of magnetization versus magnetic field of the prepared NSFs disclosed a superparamagnetic (SPM) behavior at room temperature (RT). The measurements of temperature-dependent magnetizations revealed a transition from superparamagnetic (SPM) state above blocking temperature T-B to a ferromagnetic (FM) state below T-B. The saturation magnetization and T-B decreased with the increase in co-dopant contents. In addition, the bactericidal (on the gram-positive and gram-negative bacterial strains) and anti-cancerous effectiveness of these NSFs were assessed. The cancer cells' growth inhibitory action of these NSFs was tested against both normal (HEK-293) and cancerous (HCT-116) human cells. After 48 h of treatment of the cancerous cells with the NSFs, their population was significantly dropped as shown by the MTT assay, indicating the selective inhibition of the cancer cells growth by the proposed NSFs. Conversely, the non-cancerous cells (HEK-293) population remained unaffected. The IC50 values of the NSFs-treated cancerous cells (HCT-116) were in the range of 0.74-2.35 mu g/mL. The results of the MIC and MBC assays revealed the reasonable antibacterial efficacy (growth inhibitory activity) of these NSFs when tested against the E. coli and S. aureus bacterial strains. It is established that the proposed Ce3+/Dy3+ co-activated CDMZNSFs may be beneficial for the anti-cancerous and bactericidal applications. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.
  • [ X ]
    Öğe
    Magneto-optical and microstructural properties of spinel cubic copper ferrites with Li-Al co-substitution
    (Elsevier Ltd, 2018) Slimani, Yassine; Güngüneş, Hakan; Nawaz, Muhammad; Manikandan, A.; El Sayed, H. S.; Almessiere, Munirah Abdullah; Sözeri, Hüseyin; Shirsath, Sagar E.; Ercan, İsmail; Baykal, Abdulhadi
    Nanospinel Li2xCu1-xAlyFe2-yO4 ferrites with composition x?=?y?=?0.0, 0.2, 0.3 and 0.4, were successfully synthesized via hydrothermal method. The effect of co-substitution (Li and Al) on structural, morphological and magnetic properties of CuFe2O4 nanoparticles were investigated using Powder X-ray Diffraction (XRD), Fourier-Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM) and Mossbauer spectroscopic techniques. The cation distribution of all composition was calculated. Both XRD and FT-IR analyses confirmed the synthesis of single-phase spinel cubic product for all the substitutions. Mossbauer investigation showed that the Li1+ and Al3+ ions occupied B-sites. Nonetheless, some amounts of Li1+ occupy A-site. The magnetization hysteresis loops M (H), revealed that the final products with x, y?=?0.0, 0.3 and 0.4 exhibit superparamagnetic (SPM) behavior at room temperature, however the composition x, y?=?0.2 displays a ferromagnetic-like (FM) behavior. The saturation magnetization (Ms) reduces with rising the Li and Al contents. Compared to pristine CuFe2O4 spinel, the remanent magnetization (Mr), coercive field (Hc) and the magneto-crystalline anisotropy fields (Ha) improved for products synthesized with x, y?=?0.2 and then decrease for x, y?=?0.3 and 0.4. The squareness ratio Mr/Ms are less than 0.500, which suggest the single domain nanoparticles with uniaxial anisotropy for Li2xCu1–xAlyFe2-yO4 (0.0?? x, y???0.4) nanoparticles. The magneto-crystalline anisotropy constant (Keff) value is improved for Li0.8Cu0.6Al0.2Fe1.8O4 (i.e. x, y?=?0.2) magnetic nanoparticles and then decreased for higher Li and Al contents, due to the replacement of Cu and Fe ions with respectively Li and Al ions.
  • [ X ]
    Öğe
    Magneto-optical properties of BaCryFe12?yO19 (0.0???y???1.0) hexaferrites
    (Elsevier B.V., 2018) Asiri, Sarah Mousa; Güner, Sadık; Demir Korkmaz, Ayşe; Amir, Md.; Mujasam Batoo, Khalid; Almessiere, Munirah Abdullah; Güngüneş, Hakan; Sözeri, Hüseyin; Baykal, Abdulhadi
    In this study, nanocrystalline BaCryFe12?yO19 (0.0???y???1.0) hexaferrite powders were prepared by sol–gel auto combustion method and the effect of Cr3+ ion substitution on morphology, structure, optic and magnetic properties of Barium hexaferrite were investigated. X-ray powder diffraction (XRD) analyses confirmed the purity of all samples. The XRD data shows that the average crystallite size lies between 60.95?nm and 50.10?nm and same was confirmed by Transmission electron microscopy. Transmission electron and scanning electron microscopy analyses presented the hexagonal morphology of all products. The characteristic hysteresis (?-H) curves proved the ferromagnetic feature of as grown nanoparticle samples. Specific saturation magnetization (?s) drops from 46.59 to 34.89?emu/g with increasing Cr content while the coercive field values lie between 770 and 1652?Oe. The large magnitude of the magnetocrystalline (intrinsic) anisotropy field, (Ha) between 11.0 and 12.6?kOe proves that all products are magnetically hard. The energy band gap values decrease from 2.0?eV to 1.84?eV with increasing Cr content. From 57Fe Mössbauer spectroscopy, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values were determined and discussed.
  • Küçük Resim
    Öğe
    Manganese/yttrium codoped strontium nanohexaferrites: Evaluation of magnetic susceptibility and mossbauer spectra
    (MDPI AG, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Baykal, Abdulhadi; Trukhanov, Sergei Valentinovich; Trukhanov, Alex V.
    Abstract: Manganese (Mn)- and yttrium (Y)-substituted Sr-nanohexaferrites (MYSNHFs) of composition Sr1_xMnxFe12_xYxO19 (with 0.0 ? x ? 0.5) were prepared by citrate sol-gel autocombustion method. As-prepared MYSNHFs were characterized via diverse analytical techniques to determine the influence of Mn and Y cosubstitution on their microstructures and magnetic properties. 57Fe Mössbauer spectra of the MYSNHFs were used to evaluate the variation in the line width, isomer shift, quadrupole splitting, and hyperfine magnetic field values. It was shown that the dopant ions could preferentially occupy the 12k, 4f2, and 2b sites. Furthermore, the observed shift in the blocking temperatures of the studied MYSNHFs towards lower values with rising Mn2+ and Y3+ contents was attributed to the overall particles size reduction. Meanwhile, the AC susceptibility of the proposed MYSNHFs revealed that the magnetic interactions were weakened with the increase in dopant contents which was ascribed to the replacement of both Sr2+ and Fe3+ ions by the Mn2+ and Y3+ dopants.
  • [ X ]
    Öğe
    Ni0.4Cu0.2Zn0.4TbxFe2-xO4 nanospinel ferrites: Ultrasonic synthesis and physical properties
    (Elsevier, 2019) Slimani, Yassine; Almessiere, Munirah Abdullah; Demir Korkmaz, Ayşe; Güner, Sadık; Güngüneş, Hakan; Sertkol, Murat; Baykal, Abdulhadi
    The Fe3+ ions were replace with Tb3+ ions as highly paramagnetic rare earth element within the structure of Ni0.4Cu0.2Zn0.4Fe2O4 nano-spinel ferrites (NSFs). The structural, magnetic, spectroscopic and optic properties have been studied in details. All products have been synthesized via ultrasonic approach via Qsonica ultrasonic homogenizer, frequency: 20 kHz and power 70 W for 60 min. No annealing or calcination process was applied for any product. The microstructural analysis of products has been done via X-ray powder ciiffractometry (XRD) which presented the cubic spinel structure with nanosized distribution of all. The cubic morphology of all products were confirmed by both HR-TEM and FE-SEM. Optical band gap (E-g) values were assessed by applying %DR (percent diffuse reflectance) analysis and Kubelka-Munk theory. The Tauc schemes showed that E-g values are in a narrow range (1.87-1.98 eV). The quadrupole splitting, line width, hyperfine magnetic field, isomer shift values and cation distribution have been determined from Fe-57 Mossbauer analysis. The magnetic properties of various nanoparticles have been obtained from VSM (vibration sample magnetometer) measurements at 10 and 300 K (RT). The magnetic results revealed superparamagnetic and soft ferromagnetic traits at 10 and 300 K, respectively. M-s (saturation magnetization) and M-r (remanence) initially increase with increasing Tb(3+ )substituting level up to x = 0.06 then diminish for further x values. H-c (coercivity) shows an opposite variation tendency of M-s and M-r. The observed magnetic traits are deeply discussed in relation with the structure, morphology, magnetic moments and cation distributions.