AN INVESTIGATION ON THE FORMATION OF STRONTIUM HEXAFERRITE NANO-POWDER BY A SOL-GEL AUTO-COMBUSTION METHOD IN THE PRESENCE OF SURFACTANT USING DIFFERENT BASIC AGENTS

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3159-3164 ◽  
Author(s):  
S. ALAMOLHODA ◽  
S. A. SEYYED EBRAHIMI ◽  
A. BADIEI
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Strontium Hexaferrite ◽  
Line Broadening ◽  
Hard Magnetic Material ◽  
Nano Powder ◽  
Auto Combustion ◽  
Scherrer Formula

Strontium hexaferrite is a hard magnetic material and has been extensively used as a permanent magnet. In this work a novel sol-gel auto-combustion method was used to synthesize ultra fine strontium hexaferrite. The investigations show that the model of combustion changes with the change of basic agent. The XRD results show that using ammonia or trimethylamine does not change the composition of the combustion product and it also shows that the surfactant burns completely during the combustion process. The average crystallite size of hexaferrite powders was also measured by X-ray line broadening technique employing Scherrer formula. The results show that changing the basic agent makes the particle size of the final product much smaller. Basic agent also affects the formation temperature of the single phase strontium hexaferrite.

scholarly journals Y3+ substituted Sr-hexaferrites: sol-gel synthesis, structural, magnetic and electrical characterization

Cerâmica ◽  
2019 ◽  
Vol 65 (374) ◽  
pp. 274-281 ◽  
Author(s):  
S. S. Satpute ◽  
S. R. Wadgane ◽  
S. R. Kadam ◽  
D. R. Mane ◽  
R. H. Kadam
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Combustion Method ◽  
Hexagonal Structure ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
Auto Combustion

Abstract Y3+ substituted strontium hexaferrites having chemical composition SrYxFe12-xO19 (x= 0.0, 0.5, 1.0, 1.5) were successfully synthesized by sol-gel auto-combustion method. The structural and morphological studies of prepared samples were investigated by using X-ray diffraction technique, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy. The X-ray diffraction pattern confirmed the single-phase hexagonal structure of yttrium substituted strontium ferrite and the lattice parameters a and c increased with the substitution of Y3+ ions. The crystallite size also varied with x content from 60 to 80 nm. The morphology was studied by FE-SEM, and the grain size of nanoparticles ranged from 44 to 130 nm. The magnetic properties were investigated by using vibrating sample magnetometer. The value of saturation magnetization decreased from 49.60 to 35.40 emu/g. The dielectric constant decreased non-linearly whereas the electrical dc resistivity increased with the yttrium concentration in strontium hexaferrite.

scholarly journals THE EFFECT OF HIGH ENERGY MILLING ON THE SR-HEXAFERRITE NANOCRYSTALLINE POWDER SYNTHESIZED BY A SOL-GEL AUTOCOMBUSTION METHOD

2012 ◽  
Vol 05 ◽  
pp. 765-770
Author(s):  
S. SADEGHI-NIARAKI ◽  
S. A. SEYYED EBRAHIM ◽  
SH. RAYGAN
Keyword(s):  
Ball Mill ◽  
Sol Gel ◽  
Combustion Method ◽  
High Energy ◽  
Subsequent Annealing ◽  
Strontium Hexaferrite ◽  
Nanocrystalline Powder ◽  
X Ray ◽  
Auto Combustion ◽  
Xrd Patterns

In this research SrFe 12 O 19 nanocrystalline synthesized by sol-gel auto-combustion method and subsequent annealing at 1000°C for 1h subjected to mechanochemical treatment in a high-energy ball mill and then re-annealing. A planetary ball mill (Fritsch Pulveristte 6) was used to mill the strontium hexaferrite powder at 300 rpm in air for 10, 20 and 40 hours. The process was studied by X-ray diffraction technique and scanning electron microscopy. The X-ray study showed that SrFe 12 O 19 phase was decomposed by milling. Strontium hexaferrite and α- Fe 2 O 3 were obtained with 10 hours milling. There were α- Fe 2 O 3 and strontium hexaferrite in XRD patterns of 20 hours milled sample. With increasing of the milling time to 40 hours, strontium hexaferrite was decomposed completely. The annealing of the 20 and 40 h milled powders at 900°C for 1h led to the formation of single phase strontium hexaferrite with smaller crystallite size compare to that of the hexaferrite powder before milling and subsequent annealing.

Effect of Annealing Temperature of CoCr2O4 on Structural and Vibrational Properties

2019 ◽  
Vol 11 (11) ◽  
pp. 1079-1081 ◽  
Author(s):  
Prachi Joshi ◽  
Pallavi Saxena ◽  
M. D. Varshney ◽  
V. N. Rai ◽  
A. Mishra
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Auto Combustion ◽  
Different Temperatures ◽  
Disorder Effect ◽  
High Calcination Temperature

CoCr2O4 nanoparticles were prepared by low-temperature sol–gel auto combustion method. In this paper, we have investigated the structural behavior of CoCr2O4 nanoparticles annealed at two different temperatures (600 °C and 800 °C). From the X-ray diffraction (XRD) pattern of CoCr2O4, we have found that there is no change in crystalline structure and it was indexed in the cubic spinel structure with space group Fd3m. It was observed that average crystallite size increases with calcination temperature. High calcination temperature reduced the noise level and enhanced the accuracy of calculated parameters. For both the samples of CoCr2O4, we observed Raman scattering modes at around 471, 516, 539, 561, 590, 626 and 688 cm–1. The additional modes in vibrational spectra appear due to the disorder effect.

scholarly journals Influence of trivalent rare earth (Dy3+) ions substitution on the structural, magnetic and dielectric properties of nanosized Ni0.6Cd0.4DyxFe2‒xO4 ferrites

2020 ◽  
Author(s):  
Hemant Kumar Dubey ◽  
Preeti Lahiri
Keyword(s):  
Dielectric Constant ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Sem Images ◽  
Tem Analysis ◽  
Low Dielectric ◽  
Auto Combustion ◽  
Crystallite Sizes ◽  
High Dielectric

Abstract In the present work, Ni0.6Cd0.4DyxFe2‒xO4 (x = 0.0, 0.05, 0.10, 0.15 and 0.20) nanoparticles (NPs) were synthesized by using sol-gel auto combustion method. The structural characterization was performed by XRD, FTIR, SEM, TEM and EDS analyses. XRD patterns confirmed that the pure and dysprosium substituted Ni-Cd ferrites are in single phase spinel structures, while a trace of DyFeO3 appears as a minor phase for higher concentrations (x = 0.10, 0.15 and 0.20). The Debye‒Scherrer’s method and Williamson-Hall (W-H) method were used to evaluate the crystallite sizes and lattice strain. The average crystallite size was found to be in the range from 27 to 48 nm. FT-IR confirms the formation of spinel structure. SEM images show that reduction of grain size with Dy3+ content. Elemental composition features of samples were examined by EDS. The average particles size estimated from TEM analysis are in good agreement with results obtained from the XRD. The results showed that saturation magnetization (Ms) decreases and coercivity (Hc) increases with increase in Dy3+ concentrations. The dielectric constant and the loss tangent decrease rapidly with increasing frequency and then reaches a constant value, characteristic of normal behavior of ferrites. The dielectric constant was found to decrease with increasing Dy content in Ni-Cd ferrites. Ferrite sample with Dy3+ concentration, x = 0.05 show high dielectric constant, low dielectric loss and hence can be utilized in high frequency electrical circuits.

scholarly journals Influence of Ni substitution on structural, morphological, dielectric, magnetic and optical properties of Cu–Zn ferrite by double sintering sol–gel technique

2019 ◽  
Vol 09 (02) ◽  
pp. 1950020 ◽  
Author(s):  
Mohammad Sajjad Hossain ◽  
Yeasmin Akter ◽  
Mohammad Shahjahan ◽  
Muhammad Shahriar Bashar ◽  
Most. Hosney Ara Begum ◽  
...  
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Lattice Parameter ◽  
Munk Function ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Elemental Analyses ◽  
Gel Technique

Polycrystalline NiCuZn ferrite (NixCu[Formula: see text]Zn[Formula: see text]Fe2O4; [Formula: see text], 0.3, 0.4 and 0.5) were prepared through sol–gel auto combustion method applying double sintering technique. Structural, morphological, elemental analyses (EDS), Fourier-transform infrared spectroscopy (FTIR), Direct Current (DC) electrical resistivity, dielectric, magnetic and optical properties of prepared samples were analyzed. XRD profiles reveal the formation of simple cubic spinel structure without any traceable impurity. The average crystallite size lies within the range of 22–29[Formula: see text]nm. Lattice parameter decreases with increasing Ni concentration. Room temperature DC resistivity was recorded from [Formula: see text] to [Formula: see text][Formula: see text][Formula: see text][Formula: see text]cm. Both dielectric constant ([Formula: see text]) and loss factor (tan[Formula: see text]) were decreased with increase of frequency while AC conductivity increases. FTIR absorption peak occurred at three different frequency ranges at 570–577[Formula: see text]cm[Formula: see text], 1635–1662[Formula: see text]cm[Formula: see text] and 3439–3448[Formula: see text]cm[Formula: see text]. Magnetic properties were investigated by using vibrating sample magnetometer (VSM). Decreasing trends were observed for saturation magnetization ([Formula: see text]), magnetic coercivity ([Formula: see text]) and remanant magnetization ([Formula: see text]) with the increase of Ni content. Optical band gap ([Formula: see text]2.70–2.79[Formula: see text]eV) were calculated from diffuse reflectance data by using Kubelka–Munk function.

Effect of annealing temperature on structural and magnetic properties of strontium hexaferrite nanoparticles synthesized by sol–gel auto-combustion method

2015 ◽  
Vol 29 (27) ◽  
pp. 1550190 ◽  
Author(s):  
Ebrahim Roohani ◽  
Hadi Arabi ◽  
Reza Sarhaddi ◽  
Saeedeh Sudkhah ◽  
Ameneh Shabani
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Magnetic Properties ◽  
Thermogravimetric Analysis ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Combustion Method ◽  
Strontium Hexaferrite ◽  
Auto Combustion ◽  
Ft Ir

In this paper, strontium hexaferrite nanoparticles were synthesized by the sol–gel auto-combustion method. Effect of annealing temperature on crystal structure, morphology and magnetic properties of nanoparticles was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Also, the thermal decomposition of as-synthesized powdered samples has been studied by thermogravimetric analysis (TGA). The XRD patterns confirmed the formation of single phase M-type hexagonal crystal structure for powders annealed above 950[Formula: see text]C, whereas the presence of hematite ([Formula: see text]-Fe2O3) as secondary phase was also observed for sample annealed at 900[Formula: see text]C. Furthermore, the crystallinity along with the crystallite size were augmented with annealing temperature. Comparison of the FT-IR spectra of the samples before and after annealing treatment showed the existence of metal–oxygen stretching modes after annealing. The thermogravimetric analysis confirmed the thermal decomposition of as-burnt powders happened in three-stage degradation process. The TEM images showed the nanoparticles like hexagonal-shaped platelets as the size of nanoparticles increases by increasing the annealing temperature. With increasing annealing temperature, the magnetic saturation and the coercivity were increased to the maximum value of 74.26 emu/g and 5.67 kOe for sample annealed at 1000[Formula: see text]C and then decreased.

Structural and Electrical Conductivity Studies in Nickel Ferrite Nano-Particles

2013 ◽  
Vol 209 ◽  
pp. 177-181 ◽  
Author(s):  
Ram S. Barkule ◽  
D.V. Kurmude ◽  
A.V. Raut ◽  
N.N. Waghule ◽  
K.M. Jadhav ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Nickel Ferrite ◽  
Sol Gel ◽  
Chelating Agent ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion

Abstract: The magnetic nano-particles of nickel ferrite were synthesized successfully by sol-gel auto-combustion method using high purity metal nitrates and citric acid as chelating agent. The as prepared powder of nickel ferrite was sintered at 5500C for 5 hr to obtain good crystalline phase and was used for further study. The X-ray diffraction technique was employed to confirm the single phase formation of nickel ferrite nano-particles. The X-ray diffraction pattern shows the Bragg’s peak which belongs to cubic spinel structure. The values of lattice constant, X-ray density, oxygen parameter and radii of tetrahedral and octahedral sites were calculated from XRD data. The average crystallite size was estimated using Scherrer’s formula and found to be 6 nm. The temperature dependence of the electrical conductivity plot shows the kink, which can be attributed to ferromagnetic-paramagnetic transition. The activation energy obtained from resistivity plots in paramagnetic region is found to be more than that in ferrimagnetic region. The conduction mechanism in these nickel ferrite nano-particles has been discussed on the basis of hopping of electrons.

Synthesis and Dielectric Property of Perovskite-Type LaMnO3 Nanoparticle

2007 ◽  
Vol 121-123 ◽  
pp. 967-970 ◽  
Author(s):  
Jie Sun ◽  
Zhen Hua Zhang ◽  
Xiao Hui Cao
Keyword(s):  
Dielectric Property ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Combustion Process ◽  
Chelating Agent ◽  
Combustion Method ◽  
Auto Combustion ◽  
Ft Ir ◽  
Dielectric Coefficient ◽  
Perovskite Type

The perovskite-type nanocrystal LaMnO3 was prepared using sol-gel auto-combustion method with citric acid as the chelating agent. Some analytical methods consisted of FT-IR, XRD, TEM and wave-guide method were used to characterize the gel and the final products. The metal ions coordination compound, obtained from nitrate and citrate, underwent an auto-combustion process and voluminous ashes formed when calcining the complex in the air. From the result of the dielectric properity. It was shown that the dielectric coefficient curves and dielectric loss curve of LaMnO3 nanocrystals were smooth in the range of 8-11MHz. The dielectric loss can be obversed obviously in the measured range.

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