MAGNETIC PROPERTIES AND STRUCTURE OF NANO-SIZE NiZn FERRITE SYNTHESIZED BY THE REFLUXING CO-PRECIPITATION METHOD

2009 ◽  
Vol 23 (04) ◽  
pp. 633-642 ◽  
Author(s):  
YI ZHANG ◽  
QIGANG JIAO ◽  
YA ZHAI ◽  
XIAOJUN BAI ◽  
JUN DU ◽  
...  

A series of nanoparticle powders of Ni 1-x Zn x Fe 2 O 4 (x = 0, 0.3, 0.4, 0.5, 0.6 and 0.7) ferrites were synthesized by the refluxing method at relatively low temperatures. X-ray diffraction measurements were performed to yield the grain size of the particles as a function of the amount x of Zn substitution and the lattice parameter was found to increase with increasing x. Mössbauer spectroscopy was performed at room temperature. The spectra exhibit ferromagnetic hyperfine splitting sextet peaks with a doublet peak overlapped at its center as Zn contents x < 0.6. The fitted hyperfine magnetic field of the octahedral sublattice and tetrahedral sublattice all decrease with increasing Zn content. The area of the tetrahedral sublattice decreases with increasing x and that of the octahedral sites increases for low Zn concentration, as a result of substitution of iron by zinc in the tetrahedral sites. The area of the doublet increases constantly. Systematic magnetization measurements gave evidence that the doublet in the spectra originated from the superparamagnetism of the particles at room temperature as Zn content x < 0.6.

2019 ◽  
Vol 807 ◽  
pp. 50-56
Author(s):  
Yun Long Zhou ◽  
Zhi Biao Hu ◽  
Li Mei Wu ◽  
Jiao Hao Wu

Using hydrated manganese sulfate and general type graphene (GR) as raw materials, Mn3O4/GR composite has been successfully prepared by the liquid phase chemical co-precipitation method at room temperature. X-ray diffraction (XRD) was used to investigate the phase structure of Mn3O4powder and Mn3O4/GR composite; The electrochemical performances of the samples were elucidated by cyclic voltammetry and galvanostatic charge-discharge test in 0.5 mol/L Na2SO4electrolyte. The results show that the Mn3O4/GR composite possesses graphene phase and good reversibility; the composite also displays a specific capacitance of 318.8 F/g at a current density of 1 A/g.


2018 ◽  
Vol 71 (11) ◽  
pp. 914
Author(s):  
Yanfang Xia ◽  
Min Liu ◽  
Duxin Li

Co0.76Cu0.74[Fe(CN)6]·7.5H2O was prepared as a powder by a chemical co-precipitation method. The powder X-ray diffraction patterns were indexed to the typical face-centred cubic structure with the lattice parameter a 10.55(2) Å. The temperature dependence of the χ−1 curve obeys the Curie–Weiss law (χ = C/(T – θ)) in the temperature range of 180–300 K. According to Curie–Weiss law, the calculated θ value is −54.82 K. In the paramagnetic state at 300 K, the effective magnetic moment (μeff = (8χT)1/2) is 3.58 μB per formula unit. The calculated theoretical effective magnetic moment is 4.06 μB. The magnetic field cooling measurements under a 200 Oe applied magnetic field show that the saturation magnetization value at 2 K of the complex Co0.76Cu0.74[Fe(CN)6]·7.5H2O is 1.528 emu g−1.


2021 ◽  
Author(s):  
liu zhenjie ◽  
Yudai Huang ◽  
xingchao Wang ◽  
Yue Zhang ◽  
juan Ding ◽  
...  

Abstract Li4Ti5O12/V2O5 nanocomposites were synthesized by a one-pot co-precipitation method. The structure and morphology of the as-prepared materials were analyzed by X-ray diffraction and transmission electron microscopy. The results show that Li4Ti5O12/V2O5 composites with different nano size were successfully synthesized. The Li4Ti5O12/V2O5 sample (2 wt.% V2O5 addition of Li4Ti5O12) keep at a high discharge capacity of 169.9 mAh g− 1 after 150 cycles at 1 C. The existence of the V2O5 reduces the size of Li4Ti5O12, which improve the electrochemical activity of the sample.


2013 ◽  
Vol 645 ◽  
pp. 129-132 ◽  
Author(s):  
Jantasom Khanidtha ◽  
Suttinart Noothongkaew ◽  
Supakorn Pukird

SnO2-CuO nanocomposites have been synthesized with the simple co-precipitation method for gas sensing properties. Sn and CuO powder were the starting materials. The synthesized products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that SnO2-CuO nanocomposites have a tetragonal and monoclinic structure, respectively. SEM images verify that the some microballs are up to 10 µm and nanorods have a diameter range from 10-100 nm, while length ranges a few micrometers. The nanocomposite products were highly sensitivity to CO2gas at room temperature.


Author(s):  
Luciana Biazati ◽  
Lucas Lorenzini ◽  
Sandra Ferreira ◽  
Arilza Porto ◽  
Eustáquio de Castro ◽  
...  

The correlation between iron distribution in octahedral or tetrahedral sites in synthetic magnetite and zinc spinel ferrites and their catalytic properties were investigated in this work. The zinc‑doped nanomagnetites were prepared by co-precipitation method and annealed at 420 °C. X-ray diffraction, UV-Vis, X-ray absorption and 57Fe Mössbauer spectroscopies were used to identify iron sites. The obtained results showed that ZnII replaces the relatively smaller FeIII cation in the tetrahedral sites, increasing the cubic lattice dimension, and this replacement remarkably enhances the catalytic effectiveness of the Zn-spinel ferrite towards the indigo carmine degradation compared to undoped magnetite. The indigo carmine degradation experiments were carried out using photo-Fenton method in which 50 mL of indigo carmine dye aqueous solutions (20 mg L−1, pH 3.0), 20 mg ZnxFe(3-x)O4, and 2.0 mL H2O2 (aqueous solution at 0.028 mol L−1) were placed under UV light at 25 °C. Under these experimental conditions the degradation rate of indigo carmine was superior to 98%.


2020 ◽  
Vol 52 (3) ◽  
pp. 349-358
Author(s):  
Rakesh Vishwaroop ◽  
Shridhar Mathad

In this study we have investigated structural attribute of Co+2 doped MgFe2O4. Synthesis of Mg1-xCoxFe2O4 ferrite was carried out using co-precipitation method. The formation of spinal ferrite was confirmed through X-ray diffraction. Lattice parameter found to be 8.376748 ? and crystallite sizes in the range 180-365 ? are observed. Various parameters like dislocation density (?D); mechanical properties (strain), Hopping length {tetrahedral site (LA) and octahedral site (LB)}, Bond length (A-O and B-O), and Ionic radii (rA and rB) were reported. The W-H plot and Size-Strain plots were extensively studied and the results have been correlated.


2018 ◽  
Vol 15 (3) ◽  
pp. 272-278
Author(s):  
G. Muthukumar ◽  
B Arjunkumar ◽  
R. Vignesh ◽  
G. Ramalingam

Well crystallinenanostructured TiO2 powder was synthesised by Co-precipitation method using Titanium (IV) isopropoxide and CTAB are precursor materialsto maintain in 1:1 ratio concentration. The synthesised power was structurally, morphologically and optically analysed to using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-Vis absorption spectra. The betalain pigment of polluted water was prepared from Beta vulgaris extract at room temperature (RT). The 89% of betalain pigment was degraded at 40 min from Beta vulgaris extract polluted water using as-prepared TiO2 powder as a photocatalystmaterial under visible light.


2018 ◽  
Vol 778 ◽  
pp. 195-199 ◽  
Author(s):  
Nahall Niazi ◽  
Omer Farooq ◽  
Fatima Tuz Zahra ◽  
Muhammad Anis-ur-Rehman

Strontium hexaferrite is a material of choice due its various magnetic applications. Energy losses are a prominent issue in these magnetic materials. To lower these energy losses, we need to improve the resistivity by reducing eddy current losses. In this work nanoparticles of Gadolinium (Gd) doped Sr-hexaferrite (SrFe12-xGdxO19 x =0 .0, 0.1) have been synthesized by co-precipitation method. Structural analysis was done by using X-ray diffraction technique (XRD). It was found that the formation of single phase i.e. hexagonal structure has been achieved when the samples were sintered at 920°C for 20 minutes. AC electrical properties such as conductivity (𝜎ac), dielectric constant (ε′), dielectric loss (tanδ) and impedance (Z); real (Z') and imaginary (Z") parts have been studied as a function of frequency at room temperature. Aim of the work was to enhance the resistivity and was successfully achieved. Gd doped sample is proposed as an energy efficient material to be used in devices working at high frequencies.


2013 ◽  
Vol 634-638 ◽  
pp. 567-570
Author(s):  
Hai Zhao ◽  
Ke Jian Han ◽  
Yao Tong ◽  
Xiao Qi Sha ◽  
Yang Yang Li

Mn-Ce-Fe Oxide catalysts were prepared by a co-precipitation method using precipitants NH4OH. The catalysts were characterized by Powder X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET study. It was found that the samples prepared with NH4OH as a precipitator show higher surface areas and sSubscript textuperior catalytic performance at room temperature. The catalysts would reduce substantially indoor formaldehyde concentrations in the present of airstreams.


2012 ◽  
Vol 510-511 ◽  
pp. 221-226 ◽  
Author(s):  
M. Akram ◽  
M. Anis-ur-Rehman ◽  
M. Mubeen ◽  
M. Ali

Non toxicity, bio compatibility and nanometer sizes regime which is comparable to the size of a cell, makes nanocrystalline Co ferrites particles very proficient. In the present research Zn doped cobalt ferrites were prepared by the chemical co-precipitation method and characterized by X-ray diffraction (XRD) at room temperature for structural analysis. X-ray diffraction patterns confirmed the FCC spinel structure of synthesized particles. Crystallite sizes were calculated from the most intense peak (311) using the Debye-Scherrer formula. The obtained crystallite sizes were in nanometer range for all the samples synthesized at reaction temperature of 70°C. Then samples were sintered at 550°C for 2 hours, characterized again by X-ray diffraction at room temperature. The crystallite sizes and lattice constants for all the samples were calculated again from the data obtained by XRD. DC electrical resistivity and AC electrical transport properties were analyzed. The magnetic properties such as coercivity (Hc) and remanence (Mr) of Co1-xZnxFe2O4for x = 0.0, 0.2, 0.4 were measured at room temperature by vibrating sample magnetometer. Coercivity and remanence were found maximum with minimum value of Zn in Co1-xZnxFe2O4.Observed structural and conduction properties of synthesized nanomaterials were correlated.


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