Dysprosium-Substitution Induced Changes in Structural and Electrical Properties of NiCuZn Ferrites

2018 ◽  
Vol 24 (8) ◽  
pp. 5843-5848
Author(s):  
S. M Kabbur ◽  
U. R Ghodake ◽  
S. S Suryavanshi
Keyword(s):  
Spinel Phase ◽  
Sol Gel ◽  
Interfacial Polarization ◽  
Spherical Shape ◽  
Lattice Parameter ◽  
Absorption Bands ◽  
Crystal Imperfections ◽  
Transmission Electron ◽  
Structural And Electrical Properties ◽  
Induced Changes

Ni0.25Cu0.30Zn0.45DyxFe2−xO4 (x = 0.0, 0.025, 0.05, 0.075, 0.1 and 0.125 mol.%) ferrimagnetic samples have been prepared by sol–gel autocombustion route. The lattice parameter (a) increases with dysprosium concentration indicating the expansion of unit cell as observed from XRD studies. As the dysprosium content increases minor orthoferrite phase is seen in the samples. The porosities of samples increase indicting crystal imperfections. Using Hall-Williamson analysis, the crystallite size was found to vary between 24.36 nm to 37.1 nm. From Fourier transform infrared spectroscopy (FTIR), two absorption bands ν1 and ν2 corresponding to the intrinsic vibrations of tetrahedral and octahedral sites respectively are observed which confirm the spinel phase formation and ascertain the cation distribution in the samples. The transmission electron micrographs exhibit spherical shape and narrow size distribution of nanoparticles. The sintered ferrite samples exhibit usual dielectric dispersion involving Maxwell-Wagner type interfacial polarization. A decrease in dielectric constant, dielectric loss tangent and AC conductivity with frequency is observed.

Magnesium Substitution in Hydroxyapatite Synthesized by Sol-Gel Method

2012 ◽  
Vol 506 ◽  
pp. 150-153 ◽  
Author(s):  
Jutharatana Klinkaewnarong ◽  
P. Sritonwong ◽  
Ekaphan Swatsitang
Keyword(s):  
Sol Gel ◽  
Spherical Shape ◽  
Lattice Parameter ◽  
Hexagonal Structure ◽  
Line Broadening ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Pure Phase ◽  
Crystallite Sizes ◽  
Biological Performance

The ionic substitutions have been proposed as a tool to improve the biological performance of hydroxyapatite (HAp) based materials. In the present work, the systems of Ca(10-x)Mgx(PO4)6(OH)2 (MgHAp, x = 0, 1, 2, and 3) were successfully synthesized by solgel method. To obtain nanocrystalline of MgHAp, the prepared precursors were calcined in air at 600 °C for 2 h. The samples were characterized by Xray diffraction (XRD) and transmission electron microscope (TEM) observation. The XRD results confirm the formation of pure phase of HAp with the lattice parameter a in the range of 0.94170.9479 nm and c of 0.68410.6919 nm. The crystallite sizes of the powder are found to be 3546 nm as evaluated by the XRD line broadening method. The morphology of the samples are spherical shape of diameter less than 100 nm as evaluated by TEM. The corresponding selected area electron diffraction (SAED) analysis further confirms the formation of hexagonal structure of HAp.

Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core–Shell Structured Spherical Phosphors by Sol–Gel Process

2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Average Size

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

Sol–gel synthesis, structural and electrical properties of Li2CoSiO4 cathode material

2014 ◽  
Vol 07 (06) ◽  
pp. 1440001 ◽  
Author(s):  
Michał Świętosławski ◽  
Marcin Molenda ◽  
Piotr Natkański ◽  
Piotr Kuśtrowski ◽  
Roman Dziembaj ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Sol Gel ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structural And Electrical Properties ◽  
Potential Alternative ◽  
Sol Gel Synthesis ◽  
First Time

Polyanionic cathode materials for lithium-ion batteries start to be considered as potential alternative for layered oxide materials. Among them, Li 2 CoSiO 4, characterized by outstanding capacity and working voltage, seems to be an interesting substitute for LiFePO 4 and related systems. In this work, structural and electrical investigations of Li 2 CoSiO 4 obtained by sol–gel synthesis were presented. Thermal decomposition of gel precursor was studied using EGA (FTIR)-TGA method. Chemical composition of the obtained material was confirmed using X-ray diffraction and energy-dispersive X-ray spectroscopy. The morphology of β- Li 2 CoSiO 4 was studied using transmission electron microscopy. High temperature electrical conductivity of Li 2 CoSiO 4 was measured for the first time. Activation energies of the electrical conductivity of two Li 2 CoSiO 4 polymorphs (β and γ) were determined. The room temperature electrical conductivity of those materials was estimated as well.

Luminescence Properties of Sm3+/Eu3+ Co-Doped ZnO Quantum Dots

2016 ◽  
Vol 16 (4) ◽  
pp. 3597-3601
Author(s):  
Fengyi Liu ◽  
Hong Li ◽  
Yajing Hu ◽  
Na Jin ◽  
Yun Mou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Sol Gel ◽  
Spherical Shape ◽  
Hexagonal Wurtzite Structure ◽  
Luminescence Properties ◽  
Transmission Electron ◽  
Doped Zno ◽  
Zno Quantum Dots ◽  
Zno Qds ◽  
Co Doped

In order to improve luminescence properties of semiconductor ZnO quantum dots (QDs), Sm3+/Eu3+ co-doped ZnO QDs have been controllably synthesized by sol–gel method in this paper. ZnO QDs have a spherical shape with mean diameter at about 5–6 nm, which was characterized by high-resolution transmission electron microscopy (HRTEM). ZnO QDs have hexagonal wurtzite structure with parts of Sm3+ and Eu3+ incorporated into the lattice, which was demonstrated by X-ray Diffraction (XRD). Luminescence properties at room temperature (RT) of different amount of Sm3+ and 2 mol% Eu3+ doped ZnO QDs were examined in-depth by optical spectra. In contrast to the Pr3+/Eu3+ co-doped fluorescent performance researched in our previous study, the photoluminescence (PL) spectra indicates the unique luminescence properties of Sm3+/Eu3+ co-doped ZnO QDs. In addition, fluorescence lifetimes were obtained to illustrate the luminous mechanism.

scholarly journals Effect of Cu Substitution on Magnetic Properties of Co0.6Ni0.4Fe2O4 Nanoferrites

2021 ◽  
Vol 12 (2) ◽  
pp. 1899-1906
Keyword(s):  
Grain Size ◽  
Spinel Structure ◽  
Sol Gel ◽  
Combustion Method ◽  
Lattice Parameter ◽  
Fesem Image ◽  
Absorption Bands ◽  
Cu Substitution ◽  
Ferrite Structure ◽  
Auto Combustion

This work is focusing on synthesizing the cobalt nanoferrite materials substituted by copper forming Co0.6Ni0.4-xCuxFe2O4 with x = 0.0, 0.1, and 0.3 using the sol-gel auto-combustion method. The phase analysis of XRD showed the spinel structure with the lattice parameter in the range 8.36-8.39 Å. FESEM image showed the grain size initially decreasing and then increasing with Cu concentration. The FTIR curve's two absorption bands in the specified range of frequency assured the spinel nano ferrite structure. The values of remanent ratios obtained from VSM showed their isotropic nature forming single domain ferrimagnetic particles.

scholarly journals A study of micro structural, magnetic and electrical properties of La-Co-Sm nanoferrites (LCSF) synthesized by sol-gel method

2020 ◽  
Vol 10 (2) ◽  
pp. 1772
Author(s):  
Kadhum Jassem Wadi ◽  
Hayder Abdulameer Abbas ◽  
Adnan Hussein Ali ◽  
Ban Mohammed Hasan
Keyword(s):  
Electrical Properties ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Ion Concentration ◽  
Tem Analysis ◽  
Gel Method ◽  
Sol Gel Method ◽  
Structural And Electrical Properties ◽  
Lanthanum Ion ◽  
Ferromagnetic Character

A Lanthanum (La3+) doped Samarium-Cobalt nanoferrites (La_x,Co_0.2,Sm_0.2,Fe_(2-x) O_4, where x=0.0,0.5,1.0) have been synthesized by sol-gel method in citrate media. Obtained spinal ferrites micro structure properties have been investigated by XRD, FTIR, SEM-EDX, and TEM-SAED techniques. All the samples are nano in size with significant hysteresis. Micro structural analysis by XRD confirms the obtained samples showing the single phase cubic spinal structures with an average crystal size found from 12 nm to 25 nm, while the average particles sizes identified from TEM analysis are ranging from 21.5nm-26.8 nm (~23.4nm) and from 20.5 nm to 28(~26.4nm) nm for x=0.5,1.0. The lattice parameter found to be a= 8.402, 8.423, 8.467Å for the respective values of x= 0.0, 0.05, and 1.0. Electrical properties show increase in dc resistivity with increase in La3+ ion concentration. Finally, it was concluded that the doping of Lanthanum ion (La3+) in the ferrites structure is found to influencing the structural and electrical properties without scarifying the ferromagnetic character.

scholarly journals Zn2+ substituted superparamagnetic MgFe2O4 spinel-ferrites: Investigations on structural and spin-interactions

2020 ◽  
Vol 9 (5) ◽  
pp. 576-587
Author(s):  
Lakshita Phor ◽  
Surjeet Chahal ◽  
Vinod Kumar
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spinel Phase ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Spin Interactions ◽  
Transmission Electron ◽  
Maximum Magnetization ◽  
Zn Content

Abstract Nano-magnetic ferrites with composition Mg1−xZnxFe2O4 (x = 0.3, 0.4, 0.5, 0.6, and 0.7) have been prepared by coprecipitation method. X-ray diffraction (XRD) studies showed that the lattice parameter was found to increase from 8.402 to 8.424 Å with Zn2+ ion content from 0.3 to 0.7. Fourier transform infrared (FTIR) spectra revealed two prominent peaks corresponding to tetrahedral and octahedral at around 560 and 430 cm−1 respectively that confirmed the spinel phase of the samples. Transmission electron microscopy (TEM) images showed that the particle size was noted to increase from 18 to 24 nm with an increase in Zn content from x = 0.3 to 0.7. The magnetic properties were studied by vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) which ascertained the superparamagnetic behavior of the samples and contribution of superexchange interactions. The maximum magnetization was found to vary from 23.80 to 32.78 emu/g that increased till x = 0.5 and decreased thereafter. Further, X-ray photoelectron spectroscopy (XPS) was employed to investigate the chemical composition and substantiate their oxidation states.

scholarly journals Investigating the Physical Properties of Sintered Alumina in the Presence of MgO Nanopowder

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Mehran Dadkhah ◽  
Abdollah Saboori ◽  
Majid Jafari
Keyword(s):  
Electron Microscope ◽  
Physical Properties ◽  
Grain Boundaries ◽  
Spinel Phase ◽  
Sol Gel ◽  
Inert Atmosphere ◽  
Magnesium Nitrate ◽  
Nitrate Hexahydrate ◽  
Magnesium Nitrate Hexahydrate ◽  
Transmission Electron

Magnesium oxide nanopowder is synthesized using magnesium nitrate hexahydrate and oxalic acid as precursors via the sol-gel method. In order to investigate the effect of magnesia nanopowders on the physical properties of sintered alumina, 0.1, 0.3, and 0.5 wt% of MgO are added to alumina. The prepared specimens were sintered at 1570°C for 4 hours under an inert atmosphere. The morphology and size of nanopowders were characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). Structural analysis was investigated by means of Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Outcomes show that by increasing the percentage of MgO, spinel phase (MgAl2O4) has been formed in the structure of alumina. During the sintering process, spinel phase diffused through the grain boundaries and pinned the grain boundaries which led to decrease in grain sizes. So, by decreasing the grain size, the physical properties of sintered alumina have improved.

EFFECT OF SAMARIUM DOPING ON THE STRUCTURAL AND MAGNETIC PROPERTIES OF THE LITHIUM–NICKEL FERRITE

2008 ◽  
Vol 22 (21) ◽  
pp. 2027-2033 ◽  
Author(s):  
LUNHONG AI ◽  
JING JIANG ◽  
HEJUN GAO
Keyword(s):  
Magnetic Properties ◽  
Nickel Ferrite ◽  
Spinel Phase ◽  
Lattice Parameter ◽  
Particle Sizes ◽  
Vibrating Sample Magnetometer ◽  
Soft Chemistry ◽  
X Ray ◽  
Transmission Electron ◽  
Structural And Magnetic Properties

Sm -doped Li – Ni ferrites were synthesized by a soft chemistry method. The effects of Sm -doping on the structural and magnetic properties of the Li – Ni ferrites were investigated. The structural, morphological and magnetic properties of the ferrite samples were characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The results revealed that the Sm -doped samples had the single spinel phase at low Sm content. The increase in Sm content increased the lattice parameter and decreased the particle sizes. The magnetic properties of the Sm -doped Li – Ni ferrites were strongly affected by Sm content. The saturation magnetization decreased, while coercivity increased with increasing Sm content.

scholarly journals Optical Characterization of Chemically Etched Nanoporous Silicon Embedded in Sol-Gel Matrix

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
A. S. Al Dwayyan ◽  
M. Naziruddin Khan ◽  
M. S. Al Salhi
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Spherical Shape ◽  
Nanoporous Silicon ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Si Nanoparticles ◽  
The Matrix ◽  
Crystalline Nature

Nanoporous (NPs) silicon fabricated by chemical etching process in HF acid was first separated in tetrahydrofuran (THF) solvent and then incorporated into SiO2matrix. The matrix was prepared by sol gel process in which dimethylformamide (DMF) was used as drying chemical control additive (DCCA) to form crack-free dried sample. We examined the optical properties of NPs in three medium which are solvent, sol, and dried sol gel. Our observations reveal that absorption spectra of NPs silicon in THF are modified with respect to the spectra in sol gel. Significant stability in PL of NPs silicon in the sol gel is observed. Influence of matrix environment on peaks of NPs is also discussed. Surface morphology is characterized by field emission scanning electron microscopy (FESEM) which shows that the NPs silicon in THF is similar to the sol gel but becomes aggregation particle to particle. Presence of Si nanoparticles in THF and sol is confirmed by Transmission electron microscopy (TEM). The NPs silicons have mono dispersive and high crystalline nature with spherical shape of around 5 nm in sizes.

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