scholarly journals Sol-gel synthesis, crystal structure and magnetic properties of nanocrystalline praseodymium orthoferrite

Author(s):  
Xuan Vuong Bui ◽  
Anh Tien Nguyen

In this work, nano-sized crystalline praseodymium orthoferrite was successfully synthesized via sol-gel method using water – methanol co-solvent. Single-phase PrFeO3 nanoparticles were formed after annealing the precursors at 650, 750, 850, and 950 °C during 60 min. The crystal size, lattice volume and coercivity (Hc) of nanocrystalline PrFeO3 increase with the annealing temperature. The obtained praseodymium orthoferrite exhibited paramagnetic properties with Hc = 28 – 34 Oe

2016 ◽  
Vol 19 (3) ◽  
pp. 5-10
Author(s):  
Quynh Anh Bao Le ◽  
Vu Hoang Nguyen ◽  
Hoang Thi Thuy Tran ◽  
Ha Ky Phuong Huynh

In this research, strontium hexa-ferrite nanoparticles (SrFe12O19) were synthesized by sol-gel method. The crystal structure, morphology and magnetic properties of nanoparticles were investigated using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirmed the formation of single phase M-type hexagonal crystal structure for powders which was calcined above 700oC. The product shows the magnetization of 66 emu/g, which is consistent with pure hexa-ferrite obtained by other methods, and the magnetic coercivity of 6,145 kOe higher than expected for this hexa-ferrite. The powder morphology is composed of aggregates of hexagonal particles with an average particles size of above 100nm.


2013 ◽  
Vol 756 ◽  
pp. 91-98 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah

Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900 °C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900°C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-raySpectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealingtemperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. Normal 0 21 false false false MS X-NONE X-NONE MicrosoftInternetExplorer4 Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900°C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900 °C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-ray Spectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealing temperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}


Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.


2018 ◽  
Vol 735 ◽  
pp. 945-949 ◽  
Author(s):  
Shuai Zheng ◽  
Jiangying Wang ◽  
Jingji Zhang ◽  
Hongliang Ge ◽  
Zhi Chen ◽  
...  

CrystEngComm ◽  
2016 ◽  
Vol 18 (3) ◽  
pp. 407-416 ◽  
Author(s):  
K. McBride ◽  
J. Cook ◽  
S. Gray ◽  
S. Felton ◽  
L. Stella ◽  
...  

A range of lanthanum strontium manganates (La1−xSrxMnO3) where 0 ≤ x ≤ 0.4 were prepared using a modified peroxide sol–gel synthesis. The crystal structure of these materials was investigated and their potential as mediators for magnetic fluid hyperthermia was evaluated.


2012 ◽  
Vol 12 (2) ◽  
pp. 950-954 ◽  
Author(s):  
Masoud Karimipour ◽  
J. Magnus Wikberg ◽  
Nasser Shahtahmasebi ◽  
Mahmood Rezaee Rokn Abad ◽  
M. M. Bagheri-Mohagheghi ◽  
...  

2016 ◽  
Vol 34 (2) ◽  
pp. 362-367 ◽  
Author(s):  
I. Yarici ◽  
M. Erol ◽  
E. Celik ◽  
Y. Ozturk

AbstractCerium substituted yttrium iron garnet (Ce0.2Y2.8Fe5O12; Ce-YIG) nanoparticles were produced via the sol-gel method from solutions of Ce-, Y- and Fe-based precursors, a solvent and a chelating agent. The solutions were dried at 200°C and heat treated at temperatures between 800 °C and 1400°C for 3 h in air. The effects of pH and annealing temperature on the structure, phase formation, magnetic properties and crystallite size were investigated. A cubic YIG phase was obtained for the sample annealed at 1400 °C. The presented results showed that the pH value of the starting solution affects the crystal size and consequently, the saturation magnetization.


2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Ramadan Shaiboub ◽  
Noor Baa'yah Ibrahim ◽  
Mustaffa Abdullah ◽  
Ftema Abdulhade

NanoparticlesY3−xErxFe5O12(x=0.2, 1.0, and 2.0) thin films were prepared by sol-gel method and treated at 800, 900, and 1000∘C, respectively, for 2 h. The films have single phase garnet structure and the sizes of particles are in the range of 44 to 83 nm. The magnetic measurements show that the saturation magnetization decreased with increasing of Er concentration for all samples treated at different annealing temperatures. The saturation magnetization increased with the particle size due to the enhancement of the surface spin effect. The coercivity initially decreased forx=1.0and then increased forx=2.0with increasing annealing temperature.


2021 ◽  
Author(s):  
V Maphiri ◽  
L Melato ◽  
Mhlongo ◽  
TT Hlatshwayo ◽  
TE Motaung ◽  
...  

Abstract Un-doped and ZnAlxO(1.5x + 1):0.1% Tb3+ (ZAOT) nano-powders were synthesized via citrate sol-gel method. The Alx moles were varied in the range of 0.25 ≤ x ≤ 5.0. The X-ray powder diffraction (XRD) data revealed that for the x < 1.5, the prepared samples crystal structure consists of mixed phases of the cubic ZnAl2O4 and hexagonal ZnO phases, while for the x ≥ 1.5 the structure consists of single phase of cubic ZnAl2O4. This was confirmed by the Raman and Fourier-Transform Infrared (FTIR) vibrational spectroscopy. Scanning electron microscopy (SEM) showed that varying Alx moles influences the morphology while Transmission electron microscopy (TEM) shows the dual morphology at x < 1.5. The photoluminescence (PL) revealed intense and distinct emissions attributed to both the host and Tb3+ transitions. The emission intensity highly depends on the Alx moles. The International Commission on Illumination (CIE) colour chromaticity showed that the emission colour could be tuned by varying the Alx moles.


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