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    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.
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    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.
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    Magneto optical properties and hperfine interactions of Cr3+ Ion substituted copper ferrite nanoparticles
    (Springer New York LLC, 2018) Baykal, Abdulhadi; Güner, Sadık; Güngüneş, Hakan; Mujasam Batoo, Khalid; Amir, Md.; Manikandan, A.
    Spinel CuCrxFe2?xO4 (0.0???y???1.0) nanoparticles were fabricated by co-precipitation. X-ray diffraction proved the pureness and cubic crystal assembly of products which have the crystallite sizes varying between 16 and 33 nm. The cubic morphology and expected chemical composition, spectral analyses of all sample were accomplished via Scanning electron microscopy along with Energy Dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy respectively. Magnetic and optical characterization of samples were done via Vibrating sample magnetometer, Mössbauer spectroscopy and Diffuse reflectance spectroscopy. Kubelka–Munk model was applied to UV–Vis data for calculating the optical Eg (band gap) values between minimum 1.20 and maximum 1.80 eV. Mössbauer analysis determined the consequence of Cr3+ substitution on isomer shift and quadrupole splitting of all products etc. The specific magnetization (?-H) hysteresis curves have finite coercivity (in a range of 35–410 Oe) and retentivity (in a range of 0.33–3.84 emu/g) values and reveal the soft ferrimagnetic nature of spinel CuCryFe2?yO4 nanoparticles (NPs). The estimated saturation magnetization Ms value of 35.17 emu/g is maximum for pristine CuFe2O4 NPs and decreases to minimum value of 1.57 emu/g for CuCr0.4Fe1.6O4 NPs due to Cr3+ ion substitution. The calculated squareness ratios less than 0.5 assign the uniaxial anisotropy for all CuCryFe2?yO4 NPs. The magneto-crystalline anisotropy field (Ha) values less than 10.0 kOe except for the composition of CuCr0.2Fe1.8O4 NPs are other magnetic data to reveal the soft magnetic character of samples.
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    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.
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    Mössbauer studies and magnetic properties of cubic CuFe2O4 nanoparticles
    (Springer New York LLC, 2019) Amir, Md.; Güngüneş, Hakan; Slimani, Yassine; Tashkandi, N. A.; El Sayed, H. S.; Aldakheel, F.; Sertkol, Murat; Sözeri, Hüseyin; Manikandan, A.; Ercan, İsmail; Baykal, Abdulhadi
    This study reports the preparation and characterization of nanocrystalline spinel powder of cubic copper ferrite nanoparticles (NPs) which have been fabricated via a cost-effective citrate sol–gel approach. The structural and morphological properties of the nanoparticles are analyzed by X-ray diffraction (XRD), Fourier transform spectroscopy (FT-IR), and scanning electron microscopy (SEM) whereas magnetic properties and Mössbauer analysis were performed using vibrating sample magnetometer (VSM) and Mössbauer spectra, respectively, and were characterized in detail. The empirical aim of this study is to perceive the transition phase of CuFe 2 O 4 as cubic symmetry which was confirmed by SEM images, and a couple of studies reported on the cubic structure of copper ferrite and discussed the magnetic properties. However, the present study gives the detailed information of the formation of cubic structure and magnetic behavior of the CuFe 2 O 4 cubic structure. X-ray diffraction measurements of resulting NPs show that the grain size of the particles is about 42.08 nm while SEM analysis showed that the particles have cubic nanostructured shapes with non-homogeneous sizes in around 80–100 nm. From 57 Fe, Mössbauer parameters consist of one superparamagnetic doublet and superposition of four sextets. VSM result shows the enhanced superparamagnetic nature of the CuFe 2 O 4 NPs. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
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    Substitution effect of Cr 3+ on hyperfine interactions, magnetic and optical properties of Sr-hexaferrites
    (Elsevier Ltd, 2018) Slimani, Yassine; Baykal, Abdulhadi; Amir, Md.; Tashkandi, N. A.; Güngüneş, Hakan; Güner, Sadık; El Sayed, H. S.; Aldakheel, F.; Saleh, Tawfik A.; Manikandan, A.
    Chromium-substituted strontium nano-hexaferrites, SrCrxFe12-xO19 (0.0?? x???1.0), were produced by the hydrothermal route. The structure, morphology, optical and magnetic properties were studied. Crystal structure, spinel phase and functional groups were verified using X-ray diffraction and Fourier Transform Infrared spectroscopy. The average crystallites size is ranging between 50 and 67?nm. Scanning electron microscopy observations indicated that the multi-grains of the particles are aggleromated and are hexagonal in shape. The isotherm plots obtained from the nitrogen physisorption experiments showed that the mesopore area and the total pore volume decreased progressively with increasing the Cr3+ content. Besides, the band gap energy (Eg) decreases from 1.75 to 1.43?eV. The magnetic hysteresis loops showed that the produced nano-hexaferrites exhibit hard ferromagnetic-like (FM) behavior. Compared to the pristine SrFe12O19 product, the deduced saturation (Ms) and remanent (Mr) magnetizations, the coercivity (Hc) and the magnetocrystalline anisotropy field (Ha) increase for lower Cr3+ content (x???0.4) and then decrease as the Cr3+ content further increases. The squareness ratio Mr/Ms are ranging between 0.5 and 0.6, suggesting the single domain nano-sized particles with uniaxial anisotropy for various synthesized products. Mossbauer analysis was done to determine the quadrupole splitting, the isomer shift, and the hyperfine magnetic field values of all products.