scholarly journals Crystal Chemistry, Magnetic and Dielectric Properties of Nickel Doped Strontium Ferrites

2021 ◽  
Vol 12 (1) ◽  
pp. 929-939

The SrNixFe12−2xO19 (where x = 0.0–0.8) hexaferrites powders were synthesized using Co-precipitation method and the pellets were prepared at 1100 °C/4 h in muffle furnace. XRD, FTIR, SEM and EDS analysis were used to analyze the samples structural parameters. The changes in the lattice parameters ‘a’&‘c’ are due to the differences in ionic radii. The average grain size (<D>) was estimated from SEM images and found to be in between 1.713 m (x = 0) - 0.549 m (x = 1.0). Observations indicated a decrease in saturation magnetization decreased from 68 emu/g (x = 0.0) to 50 emu/g (x = 0.6) and for x > 0.6, MS increases to 64 emu/g (x = 0.8). The coercivity exhibit anisotropic variation with doping concentration. In the present investigation, the samples shows ε = 487; tanδ = 1.97 for x = 0.6, and ε = 181; tanδ = 1.01 for x = 0.8, respectively. The observed results can be explained on the basis of composition,relaxationphenomena and super exchange interaction.

Author(s):  
Nguyen Duong

NiFe2O4/ZnO core-shell nanocomposites were prepared by two-step methodology. First, NiFe2O4 nanoparticles as the cores were synthesized by using hydrothermal method, and then modified by sodium citrate. After that ZnO as the shell was coated on modified NiFe2O4 nanoparticles by two different chemical methods including hydrothermal and co-precipitation. The formation, crystal structure, morphology and magnetic properties of the uncoated and coated samples were investigated by using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometer. It was shown that the core nanoparticles are single phase of NiFe2O4 with cubic spinel structure. Sodium citrate was well bonded on the surface of the modified nanoparticles. Contributions of the phases in the coated samples as well as structural parameters were determined from XRD data on applying of Rietveld refinement analysis. Magnetization of the core can be improved by adjusting the modification steps. XRD analysis result and SEM images revealed the formation of core/shell structure in the sample coated by using co-precipitation method.


2010 ◽  
Vol 113-116 ◽  
pp. 1770-1773 ◽  
Author(s):  
Xi Hua Zhao ◽  
Min Xu

Cu(OH)2 precursor was synthesized by direct precipitation method and CuSO4 and NaOH were used as raw materials. Then, Cu(OH)2 precursor was calcined in muffle furnace at 400°C for 2h in order that CuO particle was obtained. Through the analysis of the factors affecting the CuO, the paper determined the optimum conditions for the synthesis of nano-CuO with the direct-precipitation method. Then the paper analyzed phase composition and crystal structure of samples using XRD and calculated the average grain size of samples by Scherrer formula, and observed and analyzed by TEM to characterize the morphology and particle size of samples. The optimum precipitation conditions are as follows: when the precipitation agent is 3.2:1, reaction time 40min and precipitant concentration 0.6mol.L-1. The average size of CuO particle prepared under the conditions is 18nm and the yield is 96%.


2021 ◽  
Vol 14 (5) ◽  
pp. 409-417

Abstract: Pure nickel oxide (NiO) nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO –ZnO nanocomposites were synthesized by co-precipitation method. The PXRD studies revealed that NiO, Mn2O3 and CdO possessed cubic structure, Pb2O3 possessed monoclinic structure, ZnO possessed hexagonal structure and confirmed the presence of polycrystallinity nature of NiO and Mn2O3, CdO, Pb2O3, ZnO in the nanocomposites. The average grain size of NiO nanoparticles was found to be 30.10 nm using Debye Scherer’s formula. The FESEM images of NiO nanoparticles and their nanocomposites revealed spherical shaped structure and NiO-Pb2O3 revealed needle shaped rod-like structure. EDAX analysis confirmed the composition of NiO nanoparticles and their nanocomposites. Raman spectra exhibited characteristic peaks of pure NiO and that of NiO- Mn2O3, NiO-CdO, NiO- Pb2O3, NiO-ZnO in the synthesized nanocomposites. In the PL spectra, blue and green emission was observed in the samples. UV-vis spectra revealed the absorption peaks of NiO nanoparticles and their nanocomposites. Thus, the synthesized NiO- Mn2O3, NiO-CdO, NiO - Pb2O3 and NiO-ZnO nanocomposites can be a suitable material for electrocatalysis applications. Keywords: Nickel oxide nanocomposites, Structure, Morphology, Absorption, Luminescence.


2021 ◽  
Vol 13 (5) ◽  
pp. 812-819
Author(s):  
Mohamed Helmi Hadj Alouane ◽  
Faheem Ahmed ◽  
Nermin Adel Hussein El Semary ◽  
Munirah F. Aldayel ◽  
Fatimah H. Alhaweti ◽  
...  

In this work, carbon-based nanomaterials including; carbon nanotubes (CNT) and graphene were combined with biofertilisers and tested their impact on germination of Hordeum vulgare. The interaction between nanomaterials and biofertilisers was analysed. Scanning electron microscopy (SEM) images revealed that the surface of algal cells was covered with carbon nanomaterials including graphene and CNTs. Raman studies showed the characteristic band of graphene, CNTs and Algal cells. The combination of carbon nanomaterials with biofertilizers resulted in significantly better growth than with nanomaterials individually. To prepare a more effective superfertiliser, zinc ferrites (ZnFe2O4) nanoparticles were added to the nanomaterials-biofertilisers combination. These zinc ferrites nanofertilisers had a size ranging from 8–12 nm and were prepared by co-precipitation method and used at two different doses. The results showed that the growth parameters were increased most significantly with addition of 0.25 ml of ZnFe2O4 nanoparticles. Increasing the dose caused a less increase in growth parameters. These results indicated that increase in growth parameters was dose-dependent. These results demonstrated a great promise for novel formulation of superfertiliser that significantly enhanced plant growth without pollution or excessive use of harmful chemicals for better food security and environmental sustainability.


2012 ◽  
Vol 581-582 ◽  
pp. 525-528
Author(s):  
Jia Feng Zhang ◽  
Bao Zhang ◽  
Xue Yi Guo ◽  
He Zhang Chen ◽  
Jian Long Wang ◽  
...  

The LiFe0.98Mn0.02PO4/C was synthesized by spray-drying and low temperature reduction route using FePO4•2H2O as precursor, which was prepared by a simple co-precipitation method. The LiFe0.98Mn0.02PO4/C sample was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical measurements. The XRD analysis and SEM images show that sample has the good ordered structure and spherical particle. The charge-discharge tests demonstrate that the powder has the better electrochemical properties, with an initial discharge capacity of 162.1 mAh•g−1 and 155.8 mAh•g−1 at current density of 0.1 C and 1C, respectively. The capacity retention reaches 99.4% after 100 cycles at 1C.


2012 ◽  
Vol 512-515 ◽  
pp. 535-538 ◽  
Author(s):  
Shuai Sun ◽  
Qiang Xu

A Coprecipitation Method Was Applied to Synthesize Al2O3/GdAlO3 Compound Powder, Using Ammonia as the Precipitator. Gadolinium Oxide and Aluminium Nitrate Were Used as the Raw Materials with the Eutectic Ratio( 77 mol% Al 3+ – 23 mol% Gd 3+ ). the Precursor Was Calcined at Different Temperatures from 1200 to 1600 °C. the Phase Identifications at Different Temperatures Were Characterized by X-ray Diffractometry (XRD). the Growth Morphology of Particles Were Investigated Using Field Emission Electro Microscopy (FE-SEM). the Results Reveal that GdAlO3 Crystallized Earlier than α-Al2O3. the Diffraction Peaks of α-Al2O3 Phase Were Observed after Calcination at 1300°C for 1 H. Metastable Phase Gd3Al5O12 Underwent Complete Decomposition at 1600°C for 1 H. Gadolinium Aluminate and α-Al2O3 Showed Different Growth Mechanism during the Calcination Process. the Average Grain Size of the Calcined Powder Increased from ~40 to ~900 Nm as the Calcination Temperature Increased from 1200 to 1600 °C.


2018 ◽  
Vol 6 (1) ◽  
pp. 338-346 ◽  
Author(s):  
Mohammad S. Al-Ajely ◽  
Kareema M. Ziadan ◽  
Rafed. M. Al-Bader

The aim of the present study was to prepare a calcium fluoride (CaF2NP) Nano particle which is used in dental composites as dental filling compo glass type. CaF2 Nano powders were prepared using a Co-precipitation method using binary liquid. Crystal Structural characteristics and Elemental composition of (CaF2NP) Nanoparticles were predicted by X-ray diffraction (XRD), which showed crystalline peaks of   this material. Elemental composition was obtained from EDX analysis.  Morphology and diameters of the Nano fibers were studied by scanning electron Microscope (SEM). The size of the particles was also measured from SEM images about 58 ± 21 nm.


Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1295 ◽  
Author(s):  
Daniela Predoi ◽  
Simona Liliana Iconaru ◽  
Mihai Valentin Predoi ◽  
George E. Stan ◽  
Nicolas Buton

Obtaining nanoscale materials has allowed for the miniaturization of components, which has led to the possibility of achieving more efficient devices with faster functions and much lower costs. While hydroxyapatite [HAp, Ca10(PO4)6(OH)2] is considered the most widely used material for medical applications in orthopedics, dentistry, and general surgery, the magnesium (Mg) is viewed as a promising biodegradable and biocompatible implant material. Furthermore, Mg is regarded as a strong candidate for developing medical implants due to its biocompatibility and antimicrobial properties against gram-positive and gram-negative bacteria. For this study, magnesium-doped hydroxyapatite (Ca10−xMgx (PO4)6 (OH)2, xMg = 0.1), 10MgHAp, suspensions were successfully obtained by an adapted and simple chemical co-precipitation method. The information regarding the stability of the nanosized 10MgHAp particles suspension obtained by ζ-potential analysis were confirmed for the first time by a non-destructive ultrasound-based technique. Structural and morphological studies of synthesized 10MgHAp were conducted by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) mode and scanning electron microscopy (SEM). The XRD analysis of the 10MgHAp samples confirmed that a single crystalline phase associated to HAp with an average grain size about 93.3 nm was obtained. The FTIR-ATR spectra revealed that the 10MgHAp sample presented broader IR bands with less visible peaks when compared to a well-crystallized pure HAp. The SEM results evidenced uniform MgHAp nanoparticles with spherical shape. The antimicrobial activity of the 10MgHAp suspension against gram-positive strains (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212), gram-negative strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), as well as a fungal strain (Candida albicans ATCC 90029) were evaluated.


2013 ◽  
Vol 643 ◽  
pp. 104-107
Author(s):  
Yi Jie Gu ◽  
Qing Gang Zhang ◽  
Yun Bo Chen ◽  
Hong Quan Liu ◽  
Yan Min Wang ◽  
...  

The thermodynamic analysis of Ni2+-Mn2+-NH3-OH--H2O in co-precipitation system was carried out, and the precursor Ni1/2Mn1/2(OH)2 was prepared by hydroxide co-precipitation method. The analysis showed that the best pH value of mixed solution is 11 and the ammonia concentration is 0.4 mol/L, when NaOH is precipitating agent and ammonia is chelating agent. When the pH value is 11, the SEM images confirm that the morphology of Ni1/2Mn1/2(OH)2 is the best.


2019 ◽  
Vol 9 (2) ◽  
pp. 278-284
Author(s):  
Mohammad Sabet ◽  
Marziyeh Mohammadi ◽  
Fatemeh Googhari

Background: Due to unique chemical and physical properties and potential application in many fields, nanostructured materials have attracted many attentions. Cadmium sulfide (CdS) is a semiconductor that has a wide band gap of 2.42 eV at room temperature and can be served in solar cells and photoluminescence devices. Cadmium sulfide (CdS) is a kind of attractive semiconductor material, and it is now widely used for optoelectronic applications. CdS nano and microstructures can be synthesized via different chemical methods such as microwave-solvothermal synthesis, surfactant-ligand coassisting solvothermal method and hydrothermal route. Also different morphologies of this semiconductor such as dendrites, nanorods, sphere-like, flakes, nanowires, flower-like shape triangular and hexagonal plates, were synthesized. Methods: To synthesis of the nanocomposite, a simple co-precipitation method was served. In briefly, 0.1 g of Pb(NO3)2 was dissolved in the distilled water (Solution 1). Also different aqueous solutions were made from dissolving different mole ratio of Cd(NO3)2.6H2O respect to the lead source in the water (Solution 2). Two solutions were mixed together under vigorous stirring and then S2- solution (0.02 g thiourea in the water) was added to the Pb2+/Cd2+ solution. After that 0.1 g of CTAB as surfactant was added to the final solution. Finally to the synthesis of both sulfide and oxide nanostructures, NaOH solution was added to the prepared solution to obtain pH= 10. Distilled water and absolute ethanol were used to wash the obtained precipitate and then it dried at 80 °C for 8 h. Results: From the XRD pattern it was found that the peaks placed at 24.9°, 27°, 44.1°, 48°, 52°, 54°, 57.8°, 66.8°, 71.2° are associated to CdS compound with hexagonal phase (JCPDS=00-001-0780) that belong to (100), (002), (110), (103), (112), (201), (202), (203), (211) Miller indices respectively. The Other peaks belong to PbS with hexagonal phase (JCPDS=01-078-1897), and CdO with cubic phase (JCPDS=00-001-1049). From SEM images, it was found by choosing the mole ratio to 1:1, very small and uniform particles were achieved. By increasing Pb2+/Cd2+ mole ratio to 1:2, very tiny particles aggregated together were achieved. Conclusion: The results showed that the product can adsorb extra 80% of heavy metal ions from the water. So it can be said that the nanocomposite can be used in the water treatment due to its high photocatalytic and surface adsorption activities. In other words, it can remove heavy metals from the water and also decompose organic pollutions.


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