Electrospun Cu-Co ferrite nanofibers: synthesis, structure, optical and magnetic properties, and anti-cancer activity.

In this study, we investigated Cu-Co ferrite nanofibers (NFs) that were synthesized for the first time employing the electrospinning technique. The structure, phase purity and crystallite size of all the prepared NFs were revealed by powder X-ray diffraction (PXRD) analysis. The NFs crystallized in the Fd3̄m (no. 227) space group and the cation distribution arrangement over distinct sites in their structure was analyzed. Scanning electron microscopy (SEM) together with energy-dispersive X-ray (EDX) spectroscopy analysis showed the microstructure of the NFs and verified their expected chemical compositions. High-resolution transmission electron microscopy (TEM) images confirmed the fibrous nature and the construction of the NFs. The band gap energies derived from the UV-vis reflectance spectra showed a blue shift with an increase in the amount of Cu in the sample from 1.42 eV to 1.86 eV. Magnetization (M) as a function of magnetic field (H) measurements performed at ambient and low temperatures showed the ferrimagnetic behavior of all the NFs. The magnetic parameters including coercivity (Hc), saturation magnetization (Ms), remanent magnetization (Mr), and squareness ratio were determined from the recorded magnetization curves. At 300 K, Ms was reduced from 78.8 to 42.4 emu g-1, Mr reduced from 22.8 to 7.6 emu g-1 and the Bohr magneton reduced from 3.3 to 1.8µB with an increase in the content of Cu in the samples. The same trend was observed at 10 K, where Ms was reduced from 93.7 to 50.9 emu g-1, Mr reduced from 60.9 to 35.9 emu g-1 and the Bohr magneton reduced from 3.94 to 2.16µB. Alternatively, Hc has the highest values for x = 0 (850 Oe at 300 K and 5220 Oe at 10 K) and x = 0.6 (800 Oe at 300 K and 5400 Oe at 10 K). The anti-cancer activity of the NFs was evaluated using the MTT cell viability assay, showing a reduction in the viability of both HCT-116 and HeLa cancer cells compared to non-cancerous HEK-293 cells after treatment with the NFs. Apoptotic activity was examined by DAPI staining, where treatment with the NFs induced chromatin condensation and nuclear disintegration in HCT-116 cells.

A study on the spectral, microstructural, and magnetic properties of Eu-Nd double-substituted Ba0.5Sr0.5Fe12O19 hexaferrites synthesized by an ultrasonic-assisted approach.

In this study, an examination on the spectral, microstructural, and magnetic characteristics of Eu-Nd double-substituted Ba0.5Sr0.5Fe12O19 hexaferrites (Ba0.5Sr0.5NdxEuxFe12-2xO19 (x = 0.00-0.05) HFs) fabricated by an ultrasonic-assisted approach has been presented. An UZ SONOPULS HD 2070 ultrasonic homogenizer with frequency of 20 kHz and power of 70 W was used. The chemical bonding, structure and the morphology of the products were evaluated by Fourier-Transform Infrared (FT-IR) Spectroscopy, XRD (X-ray diffraction), scanning and transmission electron microscopy and techniques. The textural properties of the prepared nanomaterials were examined by using the Brunauer-Emmett-Teller (BET) method. The magnetic properties were studied using a vibrating sample magnetometer (VSM) at room temperature (RT) and low temperature 10 K. The magnitudes of various magnetic parameters including Ms (saturation magnetization), Mr (remanence) and Hc (coercivity) were estimated and evaluated. The M-H loops revealed the hard ferrimagnetic nature for all products at both temperatures. The Ms and Mr values showed a decreasing tendency with increasing degree of Eu3+ and Nd3+ substitutions whereas Hc values displayed an increasing trend. At RT, Ms, Mr and Hc values lie in the ranges of 63.0-68.8 emu·g-1, 24.6-39.2 emu·g-1 and 2252.4-2782.1 Oe, respectively. At 10 K, the values of Ms, Mr and Hc lie between 87.5-97.1 emu·g-1, 33.5-40.1 emu·g-1 and 2060.6-2417.2 Oe, respectively. The observed magnetic properties make the prepared products promising candidates to be applied in the recording media.

Ni0.4Cu0.2Zn0.4TbxFe2-xO4 nanospinel ferrites: Ultrasonic synthesis and physical properties.

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 diffractometry (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 (Eg) values were assessed by applying %DR (percent diffuse reflectance) analysis and Kubelka-Munk theory. The Tauc schemes showed that Eg 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 57Fe 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. Ms (saturation magnetization) and Mr (remanence) initially increase with increasing Tb3+ substituting level up to x = 0.06 then diminish for further x values. Hc (coercivity) shows an opposite variation tendency of Ms and Mr. The observed magnetic traits are deeply discussed in relation with the structure, morphology, magnetic moments and cation distributions.

Structural, magnetic, optical properties and cation distribution of nanosized Co0.7Zn0.3TmxFe2-xO4 (0.0 ≤ x ≤ 0.04) spinel ferrites synthesized by ultrasonic irradiation.

This study expressed the influence of Tm substitution on the structural, optical and magnetic properties of Co-Zn spinel ferrites (Co0.7Zn0.3TmxFe2-xO4 (0.0 ≤ x ≤ 0.04)). The different compositions were synthesized by sonochemical method using Qsonica ultrasonic homogenizer, frequency: 20 kHz and power: 70 W for 60 min. XRD patterns proved the presence of single-phase spinel ferrites with crystallites size in the 8-10 nm range. Cation distribution approved the occupancy of octahedral (B) site by Tm. The morphology and the elements stoichiometry are obtainable through FE-SEM, EDX and elemental mapping. Optical band gap (Eg) values were estimated via DR % (percent diffuse reflectance) investigations and Kubelka-Munk theory. Tauc plots revealed that direct Eg values are ranging between 1.49 and 1.68 eV. The analyses of magnetization versus magnetic field, M(H), were performed. The following magnetic parameters like saturation magnetization Ms, squareness ratio (SQR = Mr/Ms), magnetic moment nB, coercivity Hc and remanence Mr have been evaluated. M(H) curves revealed the superparamagnetic (SP) at RT and ferromagnetic property at 10 K. It was showed that the Tm3+ substitutions significantly affect the magnetic properties of host spinel ferrites. An increasing trend in the Ms, Mr, Hc, and nB values was noticed for lower Tm3+ substitution content.

Sonochemical synthesis and physical properties of Co0.3Ni0.5Mn0.2EuxFe2-xO4 nano-spinel ferrites.

Nanoparticles (NPs) of composition Co0.3Ni0.5Mn0.2EuxFe2-xO4, where 0.00 ≤ x ≤ 0.10 (hereafter called CNMEuF) were synthesized by sonochemical approach using UZ SONOPULS HD 2070 ultrasonic homogenizer (frequency of 20 kHz and power of 70 W). As-synthesized samples were characterized thoroughly to determine the effects of europium ions (Eu3+) substitution on their structure, morphology and magnetic traits. Structural analyses of the synthesized NPs confirmed their high purity and crystalline cubic phases. Percent diffuse reflectance (%DR) data and Kubelka-Munk theory were exploited to evaluate the optical band gap energies of the studied CNMEuF NPs. Values of optical band gap energies obtained from the Tauc plots were observed in the range of 1.47-1.58 eV. The hysteresis loops (at room temperature and 10 K) of synthesized NPs were analyzed to determine their magnetic properties. These NPs disclosed superparamagnetic and hard ferrimagnetic character at room temperature and 10 K, respectively. With exception, the sample with x = 0.10 revealed soft ferrimagnetic behavior at 10 K. Eu3+ doping was shown to have significant influence on the structure and magnetic attributes of the proposed CNMEuF NPs. Values of various magnetic parameters of proposed compositions were reduced with the increase in Eu3+ dopant contents.

Sonochemical synthesis of Eu3+ substituted CoFe2O4 nanoparticles and their structural, optical and magnetic properties.

Magnetic, optic and microstructural properties of ultrasonically synthesized CoEuxFe2-xO4 (x ≤ 0.1) nanoferrites (NFs) have been examined in this study. After sonochemical synthesis, XRD and FT-IR analyses confirmed the purity, the structure (cubic spinel structure and Fd3m space group) and the spectral properties of the spinel ferrite samples. The spherical morphology and chemical compositions of the products were observed via transmission and scanning electron microscopes along with EDX and elemental mapping. Percent diffuse reflectance (%DR) was used for optical investigation. Optical band gaps (Eg) were estimated utilizing Kubelka-Munk theory and Tauc equation. Eg values are in a narrow band of 1.34 to 1.44 eV. The magnetic parameters like Ms (saturation magnetization), SQR = Mr/Ms (squareness ratio), nB (magnetic moment), Hc (coercivity) and Mr (remanence) have been evaluated by analyzing measurements of magnetization versus magnetic field performed at room (RT; T = 300 K) and low (T = 10 K) temperatures. It is showed that the different produced CoEuxFe2-xO4 (0.00 ≤ x ≤ 0.10) nanospinel ferrites present superparamagnetic (SPM) nature at RT. At low temperature, the various produced CoEuxFe2-xO4 (x ≤ 0.08) nanospinel ferrites display ferrimagnetic (FM) nature. With exception, the x = 0.10 sample exhibit SPM behavior at T = 10 K. It is noticed that the Eu3+ substitutions alter in a significant way on the magnetic data. A decreasing trend in the Ms, Mr and nB values was noted with Eu3+ substitutions.

Structural, magnetic, optical properties and cation distribution of nanosized Ni0.3Cu0.3Zn0.4TmxFe2-xO4 (0.0 ≤ x ≤ 0.10) spinel ferrites synthesized by ultrasound irradiation.

In this study, Tm3+ ion substituted NiCuZn nanospinel ferrites, Ni0.3Cu0.3Zn0.4TmxFe2-xO4 (0.0 ≤ x ≤ 0.10), have been synthesized sonochemically. The structural, spectroscopic, morphological, optic and magnetic investigation of the samples were done by X-ray powder diffractometry (XRD), Fourier transform infrared spectrophotometry (FT-IR), UV-Vis diffused reflectance (%DR) spectrophotometry, transmission and scanning electron microscopies (TEM and SEM) along with EDX, Vibrating sample magnetometry (VSM), respectively. The purity of prepared products were confirmed via XRD, FT-IR, EDX and elemental mapping analyses. The analyses of magnetization versus M(H) (applied magnetic field) were performed at 300 and 10 K. The following magnetic parameters like Ms (saturation magnetization), SQR = Mr/Ms (squareness ratio), nB(magnetic moment), Hc (coercivity) and Mr (remanence) have been discussed. M(H) loops revealed superparamagnetic property at RT and soft ferromagnetic nature at 10 K. It is showed that the Tm3+ substitutions significantly affect the magnetizations data. A decreasing trend in the Ms, Hc, Mr, and nB values was detected with Tm3+ substitution.

Structural, optical and magnetic properties of Tm3+ substituted cobalt spinel ferrites synthesized via sonochemical approach.

Co-Tm nano-spinel ferrite with chemical formula CoTmxFe2-xO4 (0.0 ≤ x ≤ 0.08) NPs were prepared via sonochemical approach. X-ray powder diffraction patterns, microscopic images (SEM and TEM) and infrared spectra proved the formation of Co spinel ferrite. The effect of Tm3+ substituted on spinal structure was evaluated by lattice parameters, tetrahedral and octahedral bond length and cationic distribution. The band gap energy (Eg) of samples were estimated by performing UV-Vis percent diffuse reflectance (% DR) and applying the Kubelka-Munk theory. Eg values are in an interval between 1.33 eV and 1.64 eV. The analyses of magnetization were performed at room (300 K; RT) and low (10 K) temperatures. Different magnetic parameters including coercivity Hc, saturation magnetization Ms, remanence Mr, squareness ratio (SQR = Mr/Ms) and magnetic moment nB were deduced and discussed. The results showed superparamagnetic (SPM) nature at RT for x = 0.00 and 0.02 samples. However, the other products exhibit ferromagnetic (FM) nature. At 10 K, all synthesized NPs display FM behavior. An amazing increase in the magnitudes of Ms, Mr and Hc was observed at 10 K in comparison to RT, which is principally due to the reduced thermal fluctuations of magnetic moments at lower temperatures. The Tm3+ substitution affects considerably the magnetizations data. An enhancement in the Ms, Mr, and nB was detected on increasing the Tm3+ concentration. The SQR values at RT are found to be smaller than 0.5 postulating a single domain nature with uniaxial anisotropy for all produced ferrites. However, SQRs are in the range 0.66-0.76 at 10 K, suggesting the multi magnetic domain at low temperature, except the x = 0.02 product where the SQR = 0.47 indicating the single magnetic domain. The obtained magnetic results were investigated deeply with relation to structural and microstructural properties.