Impedance Spectroscopy Study of LiTaO3 Powder Synthesized via Sol-Gel Method

2012 ◽  
Vol 545 ◽  
pp. 275-278 ◽  
Author(s):  
Lili Widarti Zainuddin ◽  
Norlida Kamarulzaman

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.

2012 ◽  
Vol 501 ◽  
pp. 76-80
Author(s):  
Mohammad Hafizuddin Haji Jumali ◽  
Siti Mariam Mohamad ◽  
Rozidawati Awang ◽  
Muhammad Yahaya ◽  
Mohd Riduan M. Said ◽  
...  

The effect of annealing temperatures on the formation of pure perovskite Na0.5Bi0.5TiO3 (NBT) based ceramics prepared by sol gel method has been investigated. The NBT sol was prepared using NaCH3COO, C6H9BiO6 and Ti(C4H9)4 with 2-methoxyethanol and glacial acetic acid were used as solvents. The BaTiO3 sol was synthesized using C4H6BaO4 and Ti(C4H9)4 with acetic acid and ethanolamine were used as solvents. The (Na0.5Bi0.5)0.96Ba0.04TiO3 (NBBT) sol was prepared by mixing appropriate amount of NBT and BaTiO3 sols. Then NBT and NBBT sols were dried at 200oC for 24 h, ground and subsequently annealed at temperatures ranging from 440oC – 640oC for 5 min. Formation of NBT and NBBT ceramics was examined using XRD technique. X-ray diffractograms reveal that the NBT ceramic with rhombohedral structure starts to form at 540oC and complete crystallization is achieved at 620oC. Addition of 4vol% of BaTiO3 sols drastically reduces the crystallization temperature of NBBT ceramic to 460oC and a pure single phase ceramic is achieved at 520oC. Despite retaining the same rhombohedral structure, the NBBT exhibits lattice parameters expansion indicating a successful Ba substitution which is also confirms by the absence of BaTiO3 peaks in the diffractograms. Both ceramics exhibit great thermal stability with additional increment in annealing temperatures.


2013 ◽  
Vol 789 ◽  
pp. 87-92 ◽  
Author(s):  
Dwita Suastiyanti ◽  
Bambang Soegijono ◽  
M. Hikam

The formation of barium hexaferrite, BaFe12O19 single phase with nanosize crystalline is very important to get the best performance especially magnetic properties. The samples were prepared by sol gel method in citric acid-metal nitrates system. Hence the mole ratios of Ba2+/Fe3+ were varied at 1:12 and 1:11.5 with pH of 7 in all cases using ammonia solution. The solution was then heated at 80-90°C for 3 to 4 hours. Then it was kept on a pre-heated oven at 150°C. The samples were then heat treated at 450°C for 24 hours. Sintering process was done at 850°C and 1000°C for 10 hours.Crystallite size was calculated by X-Ray Diffraction (XRD) peaks using scherrer formula. To confirm the formation of a single phase, XRD analyses were done by comparing the sample patterns with standard pattern. The peak shifting of pattern could be seen from XRD pattern using rocking curves at extreme certain 2θ. It was used MPS Magnet Physik EP3 Permagraph L to know magnetic characteristics. This method can produce BaFe12O19 nanosize powder, 22-34 nm for crystallite size and 55.59-78.58 nm for particle size. A little diference in nanosize affects the peak shifting of XRD pattern significantly but shows a little difference in magnetic properties especially for samples at 850°C and 1000°C with mole ratio of 1:12 respectively. The well crystalline powder is formed at mole ratio of 1:11.5 at 850°C since it has the finest particle (55.59 nm) and crystalline (21 nm), the highest remanent magnetization (0.161 T) and the lowest intrinsic coersive (275.8 kA/m). It is also fitting exactly to the standard diffraction pattern with the highest value of best Figure of Merit (FoM), 90%. XRD peak position of this sample is almost same with XRD peak position of another sample with sinter temperature 1000°C at same mole ratio.


2021 ◽  
Vol 37 (1) ◽  
pp. 177-180
Author(s):  
Alimuddin Alimuddin ◽  
Mohd Rafeeq

Synthesis of strontium oxide nanoparticles was carried out by sol –gel method using strontium nitrate and sodium hydroxide at room temperature which is very simple and cost effective. The characterization of strontium oxide nanoparticles was done using X-ray diffraction, scanning electron microscopy (SEM) and Fourier transform infra-red (FTIR). X-ray diffraction pattern indicates that the nanoparticles are crystalline in nature. The crystalline size of strontium oxide nanoparticle was calculated by Debye-Scherrer formula. The crystalline sizes are about 80nm. The morphology of nanoparticles was observed and investigated using SEM. The material at room temperature, calcined at 2000C, 400 0C and 6000C respectively shows pseudo spherical shape, cubic form and finally it becomes cylindrical this shows that there is a agglomeration with increase in temperature. FTIR spectrum of strontium oxide shows the peak at 854.64 cm-1 which is due to Sr -O bond.


2018 ◽  
Vol 8 ◽  
pp. 184798041880064 ◽  
Author(s):  
VM Maphiri ◽  
BF Dejene ◽  
TE Motaung ◽  
TT Hlatshwayo ◽  
OM Ndwandwe ◽  
...  

Mg1.5Al2O4.5: x% Eu3+ (0 ≤ x ≤ 2) nanopowders were successfully synthesized via sol–gel method. The X-ray diffraction (XRD) spectrum revealed that the Mg1.5Al2O4.5: x% Eu3+ matches the single phase of face-centred cubic MgAl2O4. The estimated average crystallite sizes calculated using the XRD spectra were found to be in the order of 4 nm. The estimated crystal size was confirmed by the high-resolution transmission electron microscopy. The energy dispersive X-ray spectroscopy confirmed the presence of all expected elementary composition (Mg, Al, O and Eu). The field emission gun scanning electron microscope showed that varying the Eu3+ concentration influence the morphology of the prepared nanophosphor. The photoluminescence results showed that the host emits the violet colour at around 382 nm, which was attributed to the defects within the band gap ( Eg) of host material. The Eu3+-doped samples showed the emission at around 560, 580, 593, 618, 655 and 704 nm which are, respectively, attributed to the 5D1 → 7F3, 5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 characteristic transitions in Eu3+. The International Commission on Illumination colour chromaticity showed that the Eu3+ doping influences the emission colour.


2012 ◽  
Vol 545 ◽  
pp. 143-147
Author(s):  
Annie Maria Mahat ◽  
Kelimah Elong ◽  
Nor Diyana Abdul Aziz ◽  
Mohd Sufri Mastuli ◽  
Norlida Kamarulzaman

Titanium dioxide powders were synthesized via a sol-gel method using titanium nitride as the precursor. The structure and morphology of the synthesized powders were investigated and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicate that pure single phase titanium dioxide of rutile structure had been obtained. It was also revealed that annealing temperature plays an important role in the formation of single phase titanium dioxide powders. Increasing heat treatments also modified the shape and surface morphology from chunks and rock-like morphology to a mixture of flaky aggregates. Conductivity studies using a.c. impedance technique was used. The conductivity of the sample annealed at 400 °C is 89 % higher than that annealed at 800 °C and attributed to the phase and morphology of the samples.


2019 ◽  
Vol 4 (1) ◽  
pp. 23-28
Author(s):  
Qurrota A’yuni ◽  
Trisna Kumala Dhaniswara

ABSTRAKMaterial FeF3 dapat diaplikasikan dalam berbagai bidang diantaranya sebagai material katoda untuk baterai ion litium dan katalis heterogen pada beberapa reaksi yang melibatkan sisi asam. Sintesis FeF3 dapat dilakukan melalui beberapa cara, salah satunya dengan metode sol-gel. Di dalam proses sol-gel adanya agen gelasi dapat mengontrol porositas dan sifat keasaman katalis. Pada penelitian ini dipilih agen gelasi dari senyawa alkohol yaitu metanol dan etanol. Masing-masing padatan yang telah disintesis kemudian dikarakterisasi struktur padatannya dengan difraksi sinar-X. Hasil penelitian menunjukkan bahwa padatan FeF3 telah berhasil disintesis melalui metode sol gel dengan agen gelasi yang berbeda yaitu metanol dan etanol yang masing-masing dituliskan sebagai FeF3(me) dan FeF3(et). Karakterisasi struktur padatan FeF3 menggunakan difraksi sinar-X menghasilkan difraktogram yang sesuai dengan PDF No. 85-0481 dan data ICSD kode 016671 yang memilikistruktur rhombohedral dengan space group R-3cR dan panjang kisi kristal sebesar a = b = c = 5,362 Å dengan sudut α = β = γ = 57,99°. Struktur kristal FeF3 disusun oleh ion Fe3+ dengan jari-jari 0,384 Å dan ion F- dengan jari-jari 0,798 Å dengan tipe ikatan ionik. Rasio besarnya kristalinitas FeF3(et) dibandingkan dengan kristalinitasFeF3(me) sebesar 5:4.Kata kunci: FeF3, sintesis sol-gel, difraksi sinar-X, struktur padatan. ABSTRACTFeF3 material can be applied in various fields including as cathode material for lithium ion batteries and heterogeneous catalysts in some reactions involving the acid side. Synthesis of FeF3 can be done in several ways, one of them is the sol-gel method. In the sol-gel process the gelation agent can control the porosity and acidity of the catalyst. In this study, gelation agents were selected from alcohol compounds, namely methanol and ethanol. The solids that has been synthesized was then solid structure characterized by X-ray diffraction. The results showed that FeF3 solids were successfully synthesized through the sol-gel method with different gelation agents, namely methanol and ethanol, each of which was written as FeF3(me) and FeF3(et). Characterization of the solid structure of FeF3 using X-ray diffraction produces a diffractogram according to the PDF No. 85-0481 and ICSD data code 016671 which has a rhombohedral structure with space group R-3cR andcrystal lattice length of a = b = c = 5.362 Å with an angle α = β = γ = 57.99°. The crystal structure of FeF3 is composed by Fe3+ ions with radius 0.384 Å and F- ions with radius 0.798 Å with ionic bond types. The ratio of the crystallinity of FeF3(et) compared to the crystallinity of FeF3(me) is 5:4.Keywords: FeF3, sol-gel synthesis, X-ray diffraction, solid structur.


2011 ◽  
Vol 268-270 ◽  
pp. 356-359 ◽  
Author(s):  
Wen Song Lin ◽  
C. H. Wen ◽  
Liang He

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.


Nanopages ◽  
2019 ◽  
pp. 1-11
Author(s):  
G. M. Taha ◽  
M. N. Rashed ◽  
M. S. El-Sadek ◽  
M. A. Moghazy

Abstract BiFeO3 (BFO) nanopowder was synthesized in a pure form via a sol- gel method based on glycol gel reaction. Effect of drying and preheating temperature on preventing other phases was studied. Many parameters were studied as calcination temperature and time & stirring temperature as well. The prepared powder was characterized by X-Ray Diffraction of powder (XRD) and Transmission Electron Microscope (TEM). High pure BiFeO3 was obtained by preheated process at 400 °C for 0.5 h and calcination at 600 °C for 0.5 h without any impurities compared to dry at110 °C.


2011 ◽  
Vol 399-401 ◽  
pp. 1447-1450
Author(s):  
Zhi Yong Yu ◽  
Han Xing Liu

The layered LiNi1/2Mn1/2O2 cathode materials were synthesized by a sol gel method. The effects of calcination temperature and time on the structural and electrochemical properties of the LiNi1/2Mn1/2O2 were investigated. The prepared samples were characterized by X-ray diffraction (XRD) and electrochemical analysis. The results revealed that the layered LiNi1/2Mn1/2O2 material could be optimal synthesized at temperature of 900°C for 10h. The sample prepared under the above conditions has the highest initial discharge capacity of 151 mAh/g and showed no dramatic capacity fading during 20 cycles between 2.5-4.5V at a current rate of 20mA/g.


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