Chemical Synthesis of Rare Earth (La, Gd) Doped Cobalt Ferrite and a Comparative Analysis of Their Magnetic Properties

2020 ◽  
Vol 20 (8) ◽  
pp. 5239-5245
Author(s):  
Meenal Gupta ◽  
Anusree Das ◽  
Dipankar Das ◽  
Satyabrata Mohapatra ◽  
Anindya Datta
Keyword(s):  
Rare Earth ◽  
Cobalt Ferrite ◽  
Tetrahedral Site ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturation Magnetisation ◽  
Transmission Electron ◽  
Magnetization Data ◽  
Trivalent Cations ◽  
Rare Earth La

Lanthanum (La) and gadolinium (Gd) doped cobalt ferrite nanoparticles are synthesized using a soft chemical approach. The analysis of these ferrites using X-ray diffraction (XRD) and transmission electron microscopy (TEM) shows that lattice spacing decreases in the doped ferrite samples. Magnetization data indicates towards the decrease of saturation magnetisation but increase in coercivity with doping. Mössbauer spectroscopy measurements at room temperature indicate increased occupancy of trivalent cations at tetrahedral site. The addition of rare earth dopants reduces the hard-magnetic character of cobalt ferrite.

scholarly journals Designing Magnetic Layered Double Hydroxides and Two-Dimensional Magnetic Nano-Nets of Cobalt Ferrite through a Novel Approach

2018 ◽  
Vol 8 (11) ◽  
pp. 2099 ◽  
Author(s):  
Osama Saber ◽  
Abdullah Aljaafari ◽  
Sarah Asiri ◽  
Khalid Batoo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layered Double Hydroxides ◽  
Cobalt Ferrite ◽  
High Coercivity ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Double Hydroxides

The present study has a dual aim of supporting magnetic nanoparticles over the nanolayers of LDHs and designing two-dimensional magnetic nano-nets of cobalt ferrite. In this trend, nanoparticles of CoFe2O4 were prepared and supported by Co-Fe LDH through urea hydrolysis. The nanolayered structures of Co-Fe LDH were confirmed by X-ray diffraction, energy-dispersive X-ray spectrometry, FT-IR spectra, thermal analyses, and transmission electron microscopy. In addition, they indicated that 13.2% CoFe2O4 were supported over Co-Fe LDH. Transformation of the nanolayered structures of Co-Fe LDH to nano-nets was achieved by the catalytic effect of the supported CoFe2O4 nanoparticles through solvent thermal technique. X-ray diffraction patterns and transmission electron microscopy images confirmed the transformation of the supported Co-Fe LDH to nano-nets of cobalt ferrite. In order to indicate the effect of the LDH for designing the nano-nets, nanoparticles of cobalt ferrite were prepared by the same technique without LDH. The magnetic behavior of the nano-nets and the supported Co-Fe LDH were measured and compared with the nanoparticles through vibrating sample magnetometer technique. The magnetic parameters indicated that the prepared nano-nets have ferromagnetic behavior and high coercivity. However, the prepared nanoparticles revealed a superparamagnetic state and low coercivity. The experimental results concluded that the incorporation of nanoparticles with nanowires into nano-net structures has been found to be an efficient way to improve their magnetic properties and prevent their agglomerations. Finally, layered double hydroxides are an important source for constructing magnetic nanolayered structures and nano-nets.

SYNTHESIS AND CHARACTERIZATION OF BIFUNCTIONAL CoFe2O4–ZnS NANOCOMPOSITE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 237-240 ◽  
Author(s):  
J. P. BORAH ◽  
C. BORGOHAIN ◽  
K. C. SARMA ◽  
K. K. SENAPATI ◽  
P. PHUKAN
Keyword(s):  
Drug Targeting ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Magnetic Nanomaterials ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Magnetic Fluid Hyperthermia ◽  
X Ray ◽  
Transmission Electron

The synthesis of composite magnetic nanomaterials has received increasing attention due to their electronic, magnetic, catalytic, and chemical or biological sensing properties. We have prepared cobalt ferrite–zinc sulfide nanocomposites by a chemical route. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and photoluminescence spectrometer (PL). The fluorescent magnetic nanoparticles (FMNPs) had a typical diameter of 30±5 nm and saturation magnetization of 5.8 emu g-1 at room temperature. So, these FMNPs may be potentially applied in different fields such as optoelectronic devices, biolabeling, imaging, drug targeting, bioseparation, magnetic fluid hyperthermia, etc.

Synthesis and Characterization of Rare Earth (Tb3+ and Yb3+) Doped CdS/ZnS Core/Shell Nanocrystals for Enhanced Photovoltaic Efficiency

2011 ◽  
Vol 1322 ◽  
Author(s):  
Sandip Das ◽  
Krishna C. Mandal
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
Broadband Absorption ◽  
Photovoltaic Efficiency ◽  
Transmission Electron

ABSTRACTCdS host nanocrystals with 4.2-5.5 nm in diameter have been synthesized from air stable precursors via a synthetic chemical route and doped with rare earth (RE) terbium (Tb3+) and ytterbium (Yb3+) ions. RE3+-doped CdS cores were shelled by ZnS layers of different thicknesses. The resulting core/shell nanocrystals show a complete broadband absorption below 400-460 nm to the deep UV region depending on the size of the cores. RE3+-doped CdS nanocrystals showed a red shift in the emission as observed under irradiation of 302 nm UV light and was confirmed by room temperature photoluminescence (PL) measurements. The nanocrystals were further characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive x-ray (EDX) analysis. The results show that these RE3+-doped nanocrystals can be used as solar spectral matching downconversion material to enhance photovoltaic efficiency of existing solar cells.

scholarly journals Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 195
Author(s):  
Snežana S. S. Nenadović ◽  
Ljiljana M. Kljajević ◽  
Marija M. Ivanović ◽  
Miljana M. Mirković ◽  
Nadežda Radmilović ◽  
...  
Keyword(s):  
Rare Earth ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Alkali Activation ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Na Ions

The present work was focused on doping of 1% and 5% both of Nd2O3 and Sm2O3 in geopolymer gels. One of the main goals was to determine the influence of the behavior of Nd and Sm as dopants and structural nanoparticles changes of the final geopolymer formed. It is shown that the disorder formed by alkali activation of metakaolin can accommodate the rare earth cations Nd3+ and Sm3+ into their aluminosilicate framework structure. The main geopolymerization product identified in gels is Al-rich (Na)-AS-H gel comprising Al and Si in tetrahedral coordination. Na+ ions were balancing the negative charge resulting from Al3+ in tetrahedral coordination. The changes in the structures of the final product (geopolymer/Nd2O3; Sm2O3), has been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis with energy dispersive spectrometry (EDS). Nucleation at the seed surfaces leads to the formation of phase-separated gels from rare earth phase early in the reaction process. It is confirmed that Nd and Sm have been shown to form unstable hydroxides Nd(OH)3 and Sm(OH)3 that are in equilibrium with the corresponding oxides.

Preparation of Ultrafine Cobalt Ferrite Particles by Solution SHS Method

2011 ◽  
Vol 284-286 ◽  
pp. 645-648
Author(s):  
Xi En Li ◽  
Xu Hua Zhu
Keyword(s):  
Room Temperature ◽  
Cobalt Ferrite ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Reduction ◽  
Transmission Electron ◽  
Oxidation Reduction Reaction ◽  
Exothermic Oxidation ◽  
Shs Method

Nanosized CoFe2O4powders of 12nm particle size were directly prepared by solution SHS method at room temperature. The overall process involves three steps: formation of homogeneous sol; formatiom of dried gel; and combustion of the dried gel. Experiments revealed that CoFe2O4dried gel derived from citrate and nitrate sol exhibited self-propagation combustion(SHS) at room temperature once it was ignited in air. After self-propagating combustion, the gel directly transforms into nanosized CoFe2O4particles. The self-propagating combustion was considered as a heat-induced exothermic oxidation-reduction reaction between nitrate ions and carboxyl group. Differential thermal analysis-thermogravimetry (DTA-TG) was used to study the decomposition of the precursor. The structure of the nanosized CoFe2O4powders was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM).

scholarly journals Synthesis and Characteristics of Multifunctional Magneto-luminescent Nanoparticles by an Ultrasonic Wave-assisted Stӧber Method

2021 ◽  
Vol 32 (3) ◽  
pp. 75-87
Author(s):  
Tien Dung Chu ◽  
◽  
Hoang Nam Nguyen ◽  
◽  
◽  
...  
Keyword(s):  
Ultrasonic Wave ◽  
Biomedical Applications ◽  
X Ray Diffraction ◽  
Sio2 Matrix ◽  
Stöber Method ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Saturation Magnetisation ◽  
Transmission Electron ◽  
Luminescent Nanoparticles

Multifunctional magneto-luminescent nanoparticles (NPs) were synthesised by an ultrasonic wave-assisted Stöber method. The multifunctional NPs are composed of magnetic NPs (Fe3O4) and photoluminescent quantum dots (QDs) (ZnS:Mn) in amorphous silica (SiO2) matrix, which was confirmed by X-ray diffraction, Raman scattering spectroscopy, and transmission electron microscopy (TEM). The multifunctional NPs have high saturation magnetisation at room temperature simultaneously with strong photoluminescence (PL) in visible light, which is promising for biomedical applications.

Nano body-centered cubic CoFe2alloy precursor for cobalt ferrite via sonoreduction process

2008 ◽  
Vol 23 (7) ◽  
pp. 1849-1853 ◽  
Author(s):  
Maya Mohan ◽  
Vimlesh Chandra ◽  
S. Sundar Manoharan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cobalt Ferrite ◽  
Alloy Composition ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Bcc Phase ◽  
Potential Precursor

A stable nano body-centered cubic (bcc) CoFe2alloy was isolated by employing a combination of N2H4.H2O reduction and sonochemical route under basic conditions. This alloy has proved to be a potential precursor for CoFe2O4production. X-ray diffraction and transmission electron microscopy confirms the formation of a bcc phase CoFe2alloy with particle size <10 nm and spherical morphology. Thermogravimetric analysis confirmed the oxidation of the alloy composition showing a weight gain between 200 and 500 °C, which corresponds to fully oxidized CoFe2O4. A significant increase in the saturation magnetization (Ms= 230 emu/g) for the nano CoFe2alloy was observed in comparison with that of the theoretical bulk value (200 emu/g) at 300 K.

Facile Systhesis La-Doped Nanoceria and Loaded Silver Nanoparticles Scavenging Hydroxyl Radicals

2014 ◽  
Vol 933 ◽  
pp. 23-26
Author(s):  
Kun Jie Wang ◽  
Ming Liang Li ◽  
Feng Guan ◽  
Hong Xia Li ◽  
Yan Ping Wu
Keyword(s):  
Silver Nanoparticles ◽  
Rare Earth ◽  
High Resolution ◽  
Hydroxyl Radicals ◽  
Energy Dispersive Spectrometer ◽  
Rare Earth Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
La Doped

In this work, we well performed the silver nanoparticles (AgNPs) supported on rare earth oxides ,which La-doped nanoceria nanocomposites for the scavenging Hydroxyl radicals that used facile and readily synthesized strategy .The complex microstructure nanoparticles were characterized by High resolution transmission electron microsopy (HRTEM), Energy dispersive spectrometer (EDS), X-ray diffraction (XRD). This paper showed AgNPs were immobilized on an functionalized dual-rare earth oxides surface that have a potential in biomedicine like antioxidant, anti-inflammatory, antibacterial and anticancer on perspectives future.

Growth by molecular beam epitaxy of (rare-earth group V element)/III-V semiconductor heterostructures

1995 ◽  
Vol 10 (8) ◽  
pp. 1942-1952 ◽  
Author(s):  
A. Guivarc'h ◽  
A. Le Corre ◽  
P. Auvray ◽  
B. Guenais ◽  
J. Caulet ◽  
...  
Keyword(s):  
Rare Earth ◽  
Molecular Beam Epitaxy ◽  
Photoelectron Spectroscopy ◽  
Molecular Beam ◽  
High Energy ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Group V ◽  
X Ray ◽  
Transmission Electron

This paper deals with the growth by molecular beam epitaxy of semimetallic (rare-earth group V element) compounds on III-V semiconductors. Results are presented, first on the Er-Ga-As and Er-Ga-Sb ternary phase diagrams, second on the lattice-mismatched ErAs/GaAs (δa ≈ +1.6%), YbAs/GaAs (δa/a = +0.8%), and ErSb/GaSb (δa/a ≈ +0.2%) heterostructures, and third on the lattice-matched Sc0.3Er0.7As/GaAs and Sc0.2Yb0.8As/GaAs systems (δa/a < 0.05%). Finally the growth of YbSb2 on GaSb(001) is reported. The studies made in situ by reflection high-energy electron diffraction (RHEED) and x-ray photoelectron diffraction and ex situ by x-ray diffraction, transmission electron microscopy, He+ Rutherford backscattering, and photoelectron spectroscopy are presented. We discuss the atomic registry of the epitaxial layers with respect to the substrates, the appearance of a mosaic effect in lattice-mismatched structures, and the optical and electrical properties of the semimetallic films. The problems encountered for III-V overgrowth on these compounds (lack of wetting and symmetry-related defects) are commented on, and we underline the interest of compounds as YbSb2 which avoid the appearance of inversion defects in the GaSb overlayers.

Characterisation of β Phase in WE54 Magnesium Alloy

2007 ◽  
Vol 130 ◽  
pp. 155-158 ◽  
Author(s):  
Tomasz Rzychoń ◽  
Andrzej Kiełbus ◽  
Bożena Bierska-Piech
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Volume Fraction ◽  
Ageing Time ◽  
Lattice Parameter ◽  
Rare Earth Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Transmission Electron

Precipitation hardened magnesium-rare earth alloys offer attractive properties for the aerospace and racing automotive industries. The most successful magnesium alloys developed to date have been those based on the Mg-Y-Nd system identified as WE54 (Mg-5.0wt%Y-4.1wt%RE-0.5wt%Zr) and WE43 (Mg-4.0wt%Y-3.3wt%RE-0.5wt%Zr), where RE represents neodymium-rich rare earth elements. Precipitations sequence in WE-system alloys involved the formation of phases designated β”, β’, β1 and β depending on the ageing temperature. WE54 alloy with the equilibrium β-phase exhibits good ductility and medium tensile strength. The β phase precipitated in Mg-Y-Nd alloy during ageing at 300 °C was studied using X-ray diffraction analysis and transmission electron microscopy. Precipitation at 300 °C for one hour causes formation of the equilibrium β phase. This phase has an f.c.c. structure (a = 2.2 nm), which makes it isomorphous with Mg5Gd. With the prolonged ageing time at 300 °C, the volume fraction of the β phase increases and lattice parameter of the solid solution of α-magnesium decreases.

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