Y3Fe5O12 Nanoparticles Research Articles

THERMOSTIMULATED EVOLUTION OF THE CRYSTAL AND MAGNETIC STRUCTURE OF YTTRIUM FERRITE GARNET NANOPARTICLES

Iron-containing oxides form one of the most important classes of functional materials, which find a wide variety of applications. A promising approach is their use in biomedical technologies as components of systems for visualization, drug delivery, magnetic hyperthermia, etc. Nanocrystalline particles of Y3Fe5O12 garnet, obtained by glycine-nitrate combustion with subsequent thermal treatment, have been experimentally investigated. The results of studying the evolution of the crystal and magnetic structure of Y3Fe5O12 nanoparticles in dependence of the synthesis temperature are presented. A complex analysis using X-ray diffractometry, scanning electron microscopy, and Mössbauer spectroscopy has been performed. A relationship of the size and structural quality of Y3Fe5O12 nanoparticles with the observed magnetic characteristics is evealed.

Infrared Spectroscopy and Excess Conductivity Analysis for (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ Composites

In this study, the influence of adding Yttrium iron garnet (Y3Fe5O12) nanoparticles (NPs) on the microstructure and fluctuation-induced conductivity (FIC) of Cu0.5Tl0.5Ba2Ca2Cu3O10-δ (CuTl-1223) superconductor was studied. Y3Fe5O12 NPs were produced by the co-precipitation technique. By solid state route, (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ composites, with x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10 wt. % were prepared. The tetragonal unit cell parameters of (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ composites were found to be invariable with Y3Fe5O12 content. The volume fraction of the host phase was increased with Y3Fe5O12 addition till x = 0.04 wt. %. The different vibrational modes of the samples were identified through Fourier transform infrared spectroscopy (FTIR). The transition from normal to the superconducting state, for the prepared composites, was done through d.c resistivity measurements from room temperature down to zero critical temperature (T0). The Aslamazov–Larkin (AL) model was used to examine fluctuation regions in resistivity-temperature curves. At high temperatures, short wave fluctuation was observed. A cross-over between short wave fluctuation and the mean-field region was spotted at lower temperatures. The mean field region for the examined composites was composed of two-dimensional fluctuations along with one-dimensional fluctuation. The coherence length along the c-axis ζc(0), interlayer coupling (J), and anisotropy parameter (γ) were estimated from the Lawrence–Doniach (LD) model as a function of Y3Fe5O12 content.

Correction to: Structural, optical and magnetic properties of Sr and Ni co-doped YFeO3 nanoparticles prepared by simple co-precipitation method

Correction to: Structural, optical and magnetic properties of Sr and Ni co-doped YFeO3 nanoparticles prepared by simple co-precipitation method

Structural, optical and magnetic properties of Sr and Ni co-doped YFeO3 nanoparticles prepared by simple co-precipitation method

Structural, optical and magnetic properties of Sr and Ni co-doped YFeO3 nanoparticles prepared by simple co-precipitation method

Synthesis, microstructure and indentation Vickers hardness for (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ composites

High-performance and low-cost composites are engineers’ dream for technological applications. To fulfill the material for an engineering application, it is important to understand the mechanical properties of the material. The primary goal of this research is to investigate the impact of nano-sized Yttrium iron garnet (Y3Fe5O12) addition on the microstructure and mechanical properties of the polycrystalline Cu0.5Tl0.5Ba2Ca2Cu3O10-δ (CuTl-1223) superconductor. Co-precipitation and solid-state reaction methods were utilized to prepare Y3Fe5O12 nanoparticles and Cu0.5Tl0.5Ba2Ca2Cu3O10-δ superconductor, respectively. (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ nanoparticle/superconductor composites were formed by adding small contents of Y3Fe5O12 (x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10 wt%) to the CuTl-1223 matrix. The volume fraction percentage of the main phase, CuTl-1223, was increased from 87.9 to 91.4% as x was adjusted from 0.00 to 0.04 wt%. The unit cell parameters (a and c) remained unchanged following the addition of Y3Fe5O12 nanoparticles to the host CuTl-1223. The porosity percentage (P %) was decreased from 39.1 to 29.4% as x was increased from 0.00 to 0.10 wt%. Thus, the addition of Y3Fe5O12 nanoparticles has the ability to reduce weak links and voids among the CuTl-1223 superconducting grains. The grain morphology for the prepared composites was identified through scanning electron microscopy. The different elemental compositions were detected by energy-dispersive X-ray measurements. Vickers microindentation hardness test was employed to study the mechanical strength of the prepared composites. Analysis and modelling of Vickers hardness (Hv) versus test load (F) were done through various models. Meyer’s empirical law showed that all the prepared composites follow normal indentation size effect behaviour. Hays and Kendall model clarified that the applied test load was sufficient to produce both elastic and plastic deformation for the investigated samples. The elastic/plastic deformation model indicated that the prepared samples contain an elastic relaxation portion that recovers after withdrawing the test load. The proportional sample resistance and modified proportional sample resistance models confirmed the HK model findings. Moreover, the HK model was found to be the most suitable model for describing the microhardness results of the prepared samples. Furthermore, the elastic modulus (E), yield strength (Y), fracture toughness (K) and brittleness index (B) for the prepared composites were calculated as function of Y3Fe5O12 addition.

Multiferroic, Phonon and Optical Properties of Pure and Ion-Doped YFeO3 Nanoparticles

The magnetic, electric, phonon and optical properties of pure and ion-doped orthorhombic YFeO nanoparticles are studied for the first time theoretically. The spontaneous magnetization in YFeO decreases with decreasing particle size. is also shape dependent. The magnetization increases by Co and Er ion doping and decreases by Ti doping, which is caused by the different strain which appears in the nanoparticles and changes the exchange interaction constants in the doped states. The phonon energy for the mode = 149 cm and their damping decreases or increases with increasing temperature, respectively. Both show a kink near the Neel temperature, , which disappears by applying an external magnetic field. The influence of different ion doping on the band gap energy is also discussed. The doping effects can be used for different applications.

Optical and magnetic properties of YFeO3 nanoparticles synthesized by a co-precipitation method at high temperature

Optical and magnetic properties of YFeO3 nanoparticles synthesized by a co-precipitation method at high temperature

Effect of Sc Addition on Magnetic and Optical Properties of YFeO₃ Nano Particles

Multiferroic Sc-doped YFeO₃ nanoparticles were obtained by a low-temperature solid-state reaction route. It indicated that with the addition of Sc, nanosized YFeO₃ powders were obtained at 800 ℃, and the orthorhombic phase was transformed into the hexagonal structure. Magnetic hysteresis loop illustrated the magnetic property of YFeO₃ nanoparticles improved with Sc doping. The maximum magnetization of the powders was about 4.00 emu/g, showing that the energy gap can be reduced to 2.25 eV and thus the doping nanoparticles can be used in optical field. Therefore, the optical and magnetic properties of the material can be obviously enhanced with Sc doping, proving its potential application in magnetic and optical fields.

Y3Fe5O12 Nanoparticles as Efficient Pinning Centers and Temperature Dependence of the Critical Current in YBa2Cu3O7-δ Nanoparticles

Magnetic measurements have been reported in nanosized YBa2Cu3O7-δ (YBCO) cylindrical tablets doped with different proportions of Y3Fe5O12 (YIG) nanoparticles. X-ray diffraction and magnetization measurements have been achieved to characterize samples and study the influence of temperature T, applied field H, and added YIG on the intergranular critical current JC. The field has been applied perpendicular to the tablet. Temperature exponential decay of JC in YBCO nanoparticles has been observed and analyzed in the collective and correlated model framework. A two-current model has been proposed: the low-T region behavior has been attributed to the trapping effectiveness of ferromagnetic and superconducting nanoarea interfaces. In the high-T region, there are many ferromagnetic traps to ensnare a very small number of vortices leading to a flexing of JC decrease vs. T and to very low values of JC. Field dependence of JC of many tablets of YBCO with different YIG quantities has shown an optimum enhancement of JC for 0.5% of YIG in weight.

Preparation of Multiferroic YFeO3 Nanofibers and the Photocatalytic Activity under Visible Irradiation

Multiferroic YFeO3 nanofibers were prepared by electrospinning. The as-prepared nanofibers were characterized by XRD, TG-DTA, SEM and Raman spectrum. The magnetic property and photocatalytic activity of the orthorhombic YFeO3 nanofibers were also investigated. The results show that the crystal structure and morphology of the YFeO3 nanofibers were influenced by the calcination temperature. Pure orthorhomic YFeO3 nanofibers can be obtained when the temperature increased to 860 °C and they exhibit ferromagnetism with slight antiferromagnetism at room temperature. The degradation test of RhB and MB under simulated sunlight show that the YFeO3 nanofibers possess higher photocatalytic activity, compared with the YFeO3 nanoparticles.

Surface radio-mineralisation mediates chelate-free radiolabelling of iron oxide nanoparticles.

We introduce the concept of surface radio-mineralisation (SRM) to describe the chelate-free radiolabelling of iron-oxide and ferrite nanoparticles. We demonstrate the effectiveness of SRM with both 111In and 89Zr for bare, polymer-matrix multicore, and surface-functionalised magnetite/maghemite nanoparticles; and for bare Y3Fe5O12 nanoparticles. By analogy with geological mineralisation (the hydrothermal deposition of metals as minerals in ore bodies or lodes) we demonstrate that the heat-induced and aqueous SRM process deposits radiometal-oxides onto the nanoparticle or core surfaces, passing through the matrix or coating if present, without changing the size, structure, or magnetic properties of the nanoparticle or core. We show in a mouse model followed over 7 days that the SRM is sufficient to allow quantitative, non-invasive, prolonged, whole-body localisation of injected nanoparticles with nuclear imaging.

Reverse Micellar Synthesis, Characterization, Magnetic and Ferroelectric Properties of YFeO3 Nanoparticles

YFeO3 nanoparticles have been successfully synthesized through reverse micellar method for the first time using tergitol as the surfactant. The nanopowders of YFeO3 were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), selected area electron diffraction (SAED) and BET surface area studies. Powder X-ray diffraction studies reveal the highly crystalline pure phase with orthorhombic structure of YFeO3 nanoparticles. TEM and SEM studies show that the particles are uniformly distributed with hexagonal shapes with an average grain size of 60 nm. DC-magnetization measurements under an applied magnetic field of (± 60 kOe) showed the butterfly shaped hysteresis as well as the room temperature ferroelectricity confirms the multiferroic characteristics in YFeO3 nanoparticles. The dielectric constant and dielectric loss of YFeO3 nanoparticles were also studied as a function of temperature at different frequencies.

Mechanochemical Synthesis of YFeO3 Nanoparticles: Optical and Electrical Properties of Thin Films

Nanoparticles (NPs) of orthorhombic YFeO3, has been successfully synthesized via an uncomplicated mechanochemical method from yttrium and iron chloride salts in a basic medium. The YFeO3 NPs were characterized by micro-Raman and Fourier-transform infrared spectroscopy. Their crystalline structure and average diameter of 30 nm was determined from X-ray powder diffraction pattern and by transmission electron microscopy images. Thin films (TF) of these NPs in polystyrene were prepared by spin coating in order to study their electrical and optical properties, as well as to verify their possible application in the manufacture of optoelectronic devices. UV–visible diffuse reflectance was performed for YFeO3 NPs and for YFeO3 TF and optical band gaps of 2.38 and 3.7 eV, respectively, were estimated from optical absorption measurements. The electrical conductivity of the YFeO3 TF was evaluated in a glass/ITO/YFeO 3 TF/Ag device. At low voltages, electric current in the forward direction was found to obey an ohmic I–V relationship; at higher voltages, the behavior of the film in the device is defined by a Space Charge Limited Current model and, at around 1 V, current saturation. These results suggest the possibility of using YFeO3 TF in the production of dielectric layers in electronic or optoelectronic devices.

Using magnetic materials to harvest microalgal biomass: evaluation of harvesting and detachment efficiency

ABSTRACTUsing naked iron oxide (Fe3O4) and yttrium iron oxide (Y3Fe5O12) nanoparticles as flocculants, the harvesting efficiency of Chlorella vulgaris biomass was investigated. The harvesting process includes two steps, which are the separation of microalgae from the culture solution with the magnetic nanoparticles and then the separation of the algae from the magnetic nanoparticles. The optimal dosages and pH values for the magnetic harvesting of microalgal biomass were determined. Results showed that Y3Fe5O12 nanoparticles were more efficient in microalgal biomass harvesting than Fe3O4 nanoparticles. In an effort to achieve more than 90% of harvesting efficiency, optimal dosages for Fe3O4 and Y3Fe5O12 to harvest microalgal biomass were 10 and 2.5 g/L, while the appropriate pH values were 6.2 and 7.3, respectively. The harvesting efficiency of Fe3O4 and Y3Fe5O12 nanoparticles increased as the pH value decreased. The experimental results also showed that under a higher pH value Fe3O4 nanoparticles were much easier to be separated from the flocs than Y3Fe5O12. 62.9% of Fe3O4 nanoparticles could be de-attached from the aggregates, when the floc pH value reached 12.3.

Multifunctional properties and applications of yttrium ferrite nanoparticles prepared by citrate precursor route

Yttrium Ferrite nanoparticles were prepared by citrate precursor method at reasonably low temperature. Morphological and elemental studies reveal the formation of monophasic orthorhombic YFeO3 nanoparticles with fairly uniform distribution of nearly spherical particles, high specific surface area of ~338m2/g and visible band gap of 2.5eV. The electrical properties (i.e. dielectric and conductivity) were estimated from ac spectroscopic data as a function of temperature. The wasp-waisted shaped hysteresis loop displayed low Hc of 280Oe, Ms of 2.0emug−1 and Mr of 0.45emug−1 indicating canted antiferromagnetism with weak ferromagnetic behaviour. In addition to ferromagnetism, a room temperature ferroelectric loop confirmed the multiferroic behaviour of the materials. The humidity sensing properties were investigated from 8 to 80% of RH (Relative Humidity) that showed a linear response with a sensitivity of 16 nF/RH% at room temperature. Dye sensitized solar cell (DSSC) was constructed in combination with TiO2 powder to determine the photo-conversion efficiency, current density and open circuit voltage. Photocatalytic generation of hydrogen by using YFeO3 nanoparticles has also been studied under the visible light irradiations which showed a significant H2 evolution reaction rate up to 131.6μmolh−1g−1.

The influence of sintering temperature on the structure, optical and magnetic properties of Yttrium iron oxide YFeO3 prepared via Lα-alanine assisted combustion method

Single-crystalline YFeO3 nanoparticles with orthorhombic perovskite structure were synthesized via Lα-alanine assisted combustion approach. The effect of sintering temperature on the lattice and distortion parameters of the YFeO3 was discussed. The increase of the sintering temperature increased the lattice parameters and crystallite size, while decreased spontaneous strain, cell distortion, orthorhombic distortion and global instability factors. The sintering temperature did not show any significant effect of the atomic percentage of the elemental compositions of the YFeO3, where the powders showed excellent stoichiometry preserving the Y:Fe ratio (1:1). SEM micrographs showed that the YFeO3 powders exhibited quasi-rectangular shape. The magnetic properties showed an improvement of the remnant magnetization and coercivity with increasing the sintering temperature, owing to the decrease of distortion of orthorhombic perovskite structure. The diffuse reflectance UV–vis spectrophotometer was employed to investigate the optical behavior and band gap of the sintered YFeO3 powders at different temperatures. It was noticed that the reflectance bands are blue shifted and the optical band gap is decreased from 2.02 to 1.44eV. This will gave rise to the possibility to use the developed YFeO3 orthoferrites as magnetic recoverable catalyst.

Formation mechanism of nanocrystalline yttrium orthoferrite under heat treatment of the coprecipitated hydroxides

Formation of nanocrystalline yttrium orthoferrite of ∼30 nm average crystallite size from coprecipitated iron(III) and yttrium hydroxides was studied by thermo-X-ray diffractometry and simultaneous thermal analysis over 25–900°C temperature range. A mechanism of physicochemical transformations leading to the formation of YFeO3 nanoparticles was suggested.

Preparation of Nanoparticulate YFeO<sub>3</sub> by Ultrasonic Assisted Method and its Visible-Light Photocatalytic Properties

Using Fe (NO3)3⋅9H2O, Y(NO3)3⋅6H2O and citric acid as the main raw material, the YFeO3 nanoparticles were synthesized by ultrasonic assisted process and calcination. The YFeO3 nanoparticles were characterized by thermogravimetry and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the perovskite structureYFeO3 (YFeO3-800) can be obtained through the calcination of ultrasonic processed YFeO3 precursors at 800 °C, and the resulting product has a particle size of 70 nm and an optical band gap of 2.0 eV. Consequently, the YFeO3-800 nanoparticles show high photocatalytic activity for decomposition of methyl orange under visible-light irradiation.

Solvothermal Synthesis and Visible-Light Driven Photocatalytic Properties of YFeO3 Nanoparticles

This study presents a simple solvothermal method to prepare YFeO3 nanoparticles with high visible light photocatalytic activity. Metal nitrates as starting materials and ammonia as mineralizer were used in the solvothermal synthesis process. The phase undergoes change from amorphous to perovskite by increasing reaction temperature. The results showed the high crystallized YFeO3 nanoparticles, with average grain size of 40 nm, can be obtained under the synthesized temperature of 280°C. Visible-light photocatalytic experiments showed that the as-prepared YFeO3 sample with higher crystallization possessed high photocatalytic activity.

Preparation of Nanoparticulate YFeO<sub>3</sub> by Microwave Method and its Load

Using Fe (NO3)39H2O, Y(NO3)36H2O and polyvinyl alcohol as the main raw material, the YFeO3 nanoparticles were prepared by a microwave process. The YFeO3 nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the perovskite structureYFeO3 can be obtained, and the resulting product has a particle size of 70 nm and an optical band gap of 2.4 eV. The recovery of YFeO3 photocatalysts was performed by the photocatalytic experiment of load YFeO3. It is found that YFeO3 nanocrystalline photocatalysts can be efficiently recovered by magnetic polymer film load.