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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.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, AbdulhadiManganese 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.Öğe Magnetic properties and cation distribution of bimetallic (Mn–Co) doped NiFe2O4 nanoparticles(Springer New York LLC, 2017) Baykal, Abdulhadi; Eryiğit, Ş. Ş.; Amir, Md.; Güngüneş, Hakan; Sözeri, Hüseyin; Shirsath, Sagar E.; Sertkol, Murat; Asiri, Sarah MousaNickel ferrite (NiFe2O4), an inverse spinel crystal structure and a soft transition metal oxide, contemplated as a good magnetic semiconducting material with low coercivity and saturation magnetization (M s). In this study, Ni1?2xMnxCoxFe2O4 (0.0???x???0.5) nanoparticles were synthesized by the microwave assisted approach with citric acid as fuel. The effect of both cobalt and manganese substitution on the morphological, structural, and magnetic properties of the NiFe2O4 nanoparticles were studied. X-ray powder diffraction patterns confirm their complete conversion to NiFe2O4 crystal phase and the increase in lattice constant provides evidence for the effect of both Co and Mn substitution. SEM images divulge the nano-size of the prepared products with speck morphology. Magnetic properties of the final products were evaluated using Vibrating Sample Magnetometer and 57Fe Mössbauer spectroscopy. The results from both analyses suggested the M s and coercive field of NiFe2O4 NPs increases as the concentration of Co and Mn increase and Ms getting closer to the bulk value.Öğe Magnetic properties of FeMnyCoyFe2?2yO4@Oleylamine nanocomposite with cation distribution(Springer New York LLC, 2017) Amir, Md.; Demir Korkmaz, Ayşe; Baykal, Abdulhadi; Geleri, M.; Sözeri, Hüseyin; Güngüneş, Hakan; Sertkol, Murat; Shirsath, Sagar E.In this study, oleylamine (OAm) capped FeMnyCoyFe2?2yO4 (0.0???y???0.4) nanocomposites (NCs) were prepared via the polyol route and the impact of bimetallic Co3+ and Mn3+ ions on the structural and magnetic properties of Fe3O4 was investigated. The complete characterization of FeMnyCoyFe2?2yO4@OAm NCs were done by different techniques such as XRD, SEM, TGA, FT-IR, TEM, and VSM. XRD analyses proved the successful formation of mono-phase MnFe2O4 spinel cubic products free from any impurity. The average crystallite sizes were calculated in the range of 9.4–26.4 nm using Sherrer’s formula. Both SEM and TEM results confirmed that products are nanoparticles like structures having spherical morphology with small agglomeration. Ms continued to decrease up to Co3+ and Mn3+ content of y?=?0.4. Although Mössbauer analysis reveals that the nanocomposites consist three magnetic sextets and superparamagnetic particles are also formed for Fe3O4, Co0.2Mn0.2Fe2.6O4 and Co0.4Mn0.4Fe2.2O4. Cation distributions calculation was reported that Co3+ ions prefer to replace Fe2+ ions on tetrahedral side up to all the concentration while Mn3+ ions prefer to replace Fe3+ ions on the octahedral.Öğe 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, AbdulhadiThis 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.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, AbdulhadiThe 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.Öğe Structural, Magnetic, and Mossbauer Parameters' Evaluation of Sonochemically Synthesized Rare Earth Er3+ and Y3+ Ions-Substituted Manganese-Zinc Nanospinel Ferrites(Amer Chemical Soc, 2021) Almessiere, Munirah Abdullah; Güner, Sadık; Güngüneş, Hakan; Sertkol, Murat; Slimani, Yassine; Badar, Rabail; Baykal, AbdulhadiThe effect of Er3+ and Y3+ ion-co-substituted Mn0.5Zn0.5ErxYxFe2-2xO4 (MZErYF) (x <= 0.10) spinel nanoferrites (SNFs) prepared by a sonochemical approach was investigated. Surface and phase analyses were carried out using SEM, TEM, and XRD. Hyperfine parameters were determined by fitting room-temperature (RT) Mossbauer spectra. Magnetic field-dependent magnetization data unveiled the superparamagnetic nature at RT and ferrimagnetic nature at 10 K. RT saturation magnetization (M-S) and calculated magnetic moments (n(B)) are 34.84 emu/g and 1.47 mu(B), respectively, and have indirect proportionalities with increasing ion content. M-S and n(B) data have a similar trend at 10 K including remanent magnetizations (M-r). The measured coercivities (H-C) are between 250 and 415 Oe. The calculated squareness ratios are in the range of 0.152-0.321 for NPs and assign the multidomain nature for NPs at 10 K. The extracted effective magnetocrystalline constants (K-eff) have an order of 104 erg/g except for Mn0.5Zn0.5Er0.10Y0.10Fe1.80O4 SNFs that has 3.37 x 10(5) erg/g. This sample exhibits the greatest magnetic hardness with the largest magnitude of H-C = 415 Oe and an internal anisotropy field H-a = 1288 Oe among all magnetically soft NPs.Öğe Structural, magneto-optical properties and cation distribution of SrBixLaxYxFe12-3xO19 (0.0?x?0.33) hexaferrites(Elsevier Ltd, 2016) Auwal, İsmail A.; Güngüneş, Hakan; Güner, Sadık; Shirsath, Sagar E.; Sertkol, Murat; Baykal, AbdulhadiSrBixLaxYxFe12-3xO19 (00.0?x?0.33) hexaferrites were produced via sol-gel auto combustion. XRD patterns show that all the samples are single-phase M-type strontium hexaferrite (SrM). The magnetic hysteresis (?-H) loops revealed the ferromagnetic nature of nanoparticles (NPs). The coercive field decreases from 4740 Oe to 2720 Oe with increasing ion content. In particular, SrBixLaxYxFe12-3xO19 NPs with x = 0.0, 0.1, 0.2 have suitable magnetic characteristics (?s = 62.03-64.72 emu/g and Hc = 3105-4740 Oe) for magnetic recording. The intrinsic coercivity (Hci) above 15000 Oe reveals that all samples are magnetically hard materials. Tauc plots were used to specify the direct optical energy band gap (Eg) of NPs. The Eg values are between 1.76 eV and 1.85 eV. 57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting, relative area and hyperfine magnetic field values on Bi3+ La3+ and Y3+ substitutions have been determined. © 2016 Elsevier Ltd. All rights reserved.Öğe Structural, morphological, optical, cation distribution and Mössbauer analysis of Bi3+ substituted strontium hexaferrite(Elsevier Ltd, 2016) Auwal, İsmail A.; Güngüneş, Hakan; Baykal, Abdulhadi; Güner, Sadık; Shirsath, Sagar E.; Sertkol, MuratSingle-phase M-type hexagonal ferrites, SrBixFe12?xO19 (0.0?x?1.0), were prepared by a co-precipitation assisted ceramic route. The influence of the Bi3+ substitution on the crystallization of ferrite phase has been examined using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Mössbauer spectroscopy. The XRD data show that the nanoparticles crystallize in the single hexagonal magnetoplumbite phase with the crystallite size varying between 65 and 82 nm. A systematic change in the lattice constants, a=b and c, was observed because of the ionic radius of Bi3+ (1.17 Å) being larger than that of Fe3+ ion (0.64 Å). SEM analysis indicated the hexagonal shape morphology of products. From 57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values on Bi substitutions have been determined.Öğe Structural, optical and mössbauer study of Ba1???xCuxFe12O19 (0.5???x) nano hexaferrites(Springer New York LLC, 2018) Asiri, Sarah Mousa; Amir, Md.; Güner, Sadık; Güngüneş, Hakan; Mujasam Batoo, Khalid; Sertkol, Murat; Imran, Ahamad; Baykal, AbdulhadiIn this study, a novel Ba1?xCuxFe12O19 (0.5???x) nano-hexaferrites were prepared by a simple and cost-effective sol–gel auto-combustion method using barium nitrates, iron nitrate, copper (II) acetate monohydrate and citric acid, and its structural, optical properties and hyperfine interactions were reported. Structural properties were analyzed through XRD (X-ray diffraction), Scanning electron microscopy (SEM), and TEM (Transmission electron microscopy), while percent diffuse reflectance spectroscopy (DRS) and Mössbauer spectrometer were used for analyzing the optical and magnetic properties of the resultant products. The observed Mössbauer studies proved the ferromagnetic nature of nanoparticles (NPs) samples. The crystallite size (XRD) varies in a range of (23.30–35.12) nm. The direct optical energy band gap (E g ) of all samples were calculated by Tauc plots where the E g values are found in a small range of 1.97–2.15 eV. The experimental evidences signify the promising use of newly prepared nano-hexaferrites in the development of materials in various industrial devices and far better than the conventional available hexaferrites materials.Öğe Synthesis and characterization of oleylamine capped MnxFe1-xFe2O4nanocomposite: Magneto-optical properties, cation distribution and hyperfine interactions(Elsevier Ltd, 2016) Güner, Sadık; Baykal, Abdulhadi; Amir, Md.; Güngüneş, Hakan; Geleri, M.; Sözeri, Hüseyin; Shirsath, Sagar E.; Sertkol, MuratPure Fe3O4 NPs and Oleylamin (OAm) capped MnxFe1-xFe2O4 (MnxFe1-xFe2O4@OAm) (0.2 ? x ? 1.0) nanocomposites (NCs) were synthesized by the polyol route. Lattice parameter increases with increasing Mn2+ concentration, due to the respective larger ionic radius of Mn2+ ion compared with the Fe2+ ion. The VSM analyses revealed superparamagnetic characteristics of all samples. The extrapolated specific saturation magnetization (?s) values decreased from maximum 50.74 emu/g to minimum 15.34 emu/g by increasing Mn content. The particle size dependent Langevin function was applied to determine the magnetic particle dimensions (Dmag) between 9.10 nm and 21.50 nm. The observed magnetic moments of NPs and NCs are in range of (0.64–2.10) ?B and significantly less than 4 ?B of bulk Fe3O4. Magnetic anisotropy was determined as uniaxial and calculated effective anisotropy constants (Keff) are between 32.14 × 104 Erg/g and 8.71 × 104 Erg/g. The size dependent saturation magnetization suggests the existence of a magnetically dead layers around the magnetic cores for NCs between 0.72 nm and 1.29 nm. From 57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values on Mn2+ substitution have been determined. Although, the Mössbauer spectra for the sample x = 0.2 is composed of ferromagnetic sextets, paramagnetic doublet is also formed for other samples. The percent diffuse reflectance spectroscopy (DR %) and Kubelka-Munk theory were used to specify the optical properties. The estimated optical band gap (Eg) values from Tauc plots are between 1.50 eV and 2.05 eV. Increasing Mn content in NCs increased the band gap at different magnitudes.Öğe Synthesis and structural and magnetic characterization of BaZn x Fe12?x O19 hexaferrite: hyperfine interactions(Springer New York LLC, 2017) Baykal, Abdulhadi; Sözeri, Hüseyin; Güngüneş, Hakan; Auwal, İsmail A.; Shirsath, Sagar E.; Sertkol, Murat; Amir, Md.To study the effect of Zn substitution on structural magnetic properties and hyperfine interactions of barium hexaferrite, BaFe12?x Zn x O19 (0.0?x?0.3) hexaferrites were synthesized via sol-gel auto-combustion technique. Rietveld analysis of XRD powder patterns confirmed the formation of single-phase hexaferrites for all products. Due to the larger ionic size of Zn2+ as compared with Fe3+, while x increases, the lattice constant parameters increase to a small degree. Nanoplate morphology of the products is presented by SEM analyses. It was observed that both saturation magnetization and coercivity decrease in almost the same manner with zinc concentration for all substitutions. Cation distribution calculations showed that Zn2+ occupies 12k, 4 f 2, 4 f 1, and 2b sites and at the same time pushes Fe3+ ions towards 2a and 12 k 1 sites. From57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting, and hyperfine magnetic field values on Zn2+ substitution have been determined.Öğe Tailored microstructures, optical and magnetic qualities of strontium hexaferrites: Consequence of Tm3+ and Tb3+ ions Co-substitution(Elsevier Sci Ltd, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Tashkandi, Nabiha A.; Güngüneş, Hakan; Sertkol, Murat; Nawaz, Muhammad; Ercan, İsmailTerbium (Tb) and Thulium (Tm) co-doped strontium hexaferrites (SHFs), with composition SrFe12-2xTbxTmxO19 (0.00 <= x <= 0.04), were prepared via sol-gel auto-combustion method. The effect of Tb3+ and Tm3+ (as codopants) on SHFs were investigated in detail. XRD pattern of the prepared SHFs revealed the formation of M-type SHFs. A secondary phase of Fe2O3 starts to appear for x >= 0.02. The optical band gaps (E-g) of the prepared SHFs were widened with the increase in doping levels. Mossbauer study showed that the Tm3+ and Tb3+ ions have the preference to occupy 12k and 2a octahedral sites. M(H) measurements were recorded at room temperature (RT; T = 300 K) and low temperature (T = 10 K). The hysteresis loops of various SHFs revealed their ferrimagnetic (FM) nature at both RT and 10 K. Magnetic parameters including saturation magnetization (M-s), remanence (M-r), coercivity (H-c), squareness ratio (SQR = M-r/M-s) and magnetic moment (n(B)) were determined. Compared to the pristine (undoped) sample, lower content of Tm3+ and Tb3+ co-substitution (x = 0.01) improves significantly the magnetic properties of SHFs. With further increasing co-substitution contents (x > 0.01), an impurity phase appears and as a result the magnetization reduces. The observed SQR values of the proposed SHFs above 0.5 clearly indicated their single domain character with uniaxial magnetocrystalline anisotropy. Our systematic synthesis strategy and characterization may constitute a basis for achieving high quality co-doped SHFs in a customized way.Öğe Tb3+ substituted strontium hexaferrites: Structural, magnetic and optical investigation and cation distribution(Chinese Society of Rare Earths, 2019) Almessiere, Munirah Abdullah; Slimani, Yassine; Güngüneş, Hakan; Sertkol, Murat; Nawaz, Muhammad; Algarou, N. A.; Baykal, Abdulhadi; Ercan, İsmailIn this study, SrFe12?xTbxO19 (0.00 ? x ? 0.1) hexaferrites (HFs) were prepared successfully by citrate sol-gel approach. X-ray powder diffraction analyses affirm the hexagonal structure of products. Impurity phase starts to appear for x ? 0.04. The crystallites sizes were estimated to be in the range of 33–46 nm. All the products exhibit inhomogeneous distribution of grain size detected through SEM. The analyses of magnetization versus applied magnetic field, M(H), were performed. Magnetization measurements were done at room (300 K; RT) and low (10 K) temperatures. The different magnetic parameters including saturation magnetization Ms, remanence Mr, squareness ratio (SQR = Mr/Ms), coercivity Hc, and magnetic moment nB are deduced and discussed in detail. At both considered temperatures, M(H) results show ferrimagnetic nature for all compositions. It is shown that the Tb substitutions significantly affect M(H) data. A significant increase in the Ms, Mr, and nB is observed for x = 0.02 sample. The SQR values are around 0.5 indicating the single domain nature with uniaxial anisotropy. The obtained magnetic results were investigated deeply with relation to structural and microstructural properties. Mössbauer spectroscopy results were also investigated. According to Mössbauer results, the Tb3+ ions preferentially occupy 12k and 4f2 sites.Öğe The Temperature Effect on Magnetic Properties of NiFe2O4 Nanoparticles(Springer, 2018) Asiri, Sara; Sertkol, Murat; Güngüneş, Hakan; Amir, M. D.; Manikandan, Ayyar; Ercan, İsmail; Baykal, AbdulhadiIn this study, NiFe2O4 nanoparticles (NPs) were fabricated via auto citric acid sol-gel route at three different temperatures (900, 1000 and 1100 A degrees C). X-ray diffraction (XRD) and Fourier transform infrared were utilized to analyze the structural properties of magnetic nanoparticles (MNPs). XRD patterns reflect the formation of spinel ferrites without the existence of any kind of secondary phases. Morphological features of resultant MNPs were characterized by scanning electron microscopy. The XRD results show that the crystallite size increases from 30.75 to 42.32 nm with increasing the temperature of the calcination process in a distinct linear trend. The enhancement of the saturation magnetization and magnetic moment of the uniaxial NiFe2O4 NPs were studied and varying from 35 to 40 emu/g and 1.47-1.68 A mu(B,) respectively, as the temperature increases. Mossbauer parameters for different calcination temperature have been determined. The occupation ratio of Ni2+ ions at the A sites decreases from 53 to 49% with increasing calcination temperature from 900 to 1100 A degrees C.Öğe Ultrasonic synthesis, magnetic and optical characterization of Tm(3+)and Tb3+ ions co-doped barium nanohexaferrites(Academic Press Inc Elsevier Science, 2020) Almessiere, Munirah Abdullah; Slimani, Yassine; Güner, Sadık; Aldakhil, Sadal Khalid; Demir Korkmaz, Ayşe; Sertkol, Murat; Baykal, AbdulhadiThis study investigated the structural, optical and magnetic properties of BaTmxTbxFe12-2xO19(x <= 0.05) nanohexaferrites (NHFs) produced by ultrasonic assisted sol-gel combustion approach. The structure of all samples was characterized through XRD powder pattern, SEM, TEM and HR-TEM. UV-Vis diffuse reflectance studies specify that direct band gap (E-g) of pristine BaFe12O19 increases from 1.86 eV to maximum 2.55 eV due to ion substitution. The field dependent magnetization G(H) loops a 300 and 10 K were registered by applying a dc magnetic field up to +/- 10 kOe. Substitutions of Fe3+ ions by Tm3+ and Tb3+ ions affect remarkably the magnetic parameters of samples. Measured remnant magnetizations (sigma(r)) and coercivity fields (H-c) are in a range of 25.60-32.88 emu/g and 2116-4334 Oe, respectively at RT. On the other hand, estimated RT saturation magnetizations (sigma(s)) are in a range of 44.30-58.31 emu/g, and magneton numbers (n(B)) are between 8.83 and 11.72 mu(B). Magnetic parameters at 10 K have much greater magnitudes as sigma(s) = 65.11-94,12 emu/g, sigma(r) = 32.50-47.75 emu/g, n(B) = 12.96-18.91 mu(B). Coercive fields sharply decreased to a range of 720-2068 Oe at 10 K. All samples exhibit strong ferromagnetic features at both temperatures. The observed magnetic features assign that the ultrasonically produced NPs hexaferrites are suitable materials for high-density recording media and permanent magnets.
