scholarly journals Structural, electrical and magnetic behaviour of undoped and nickel doped nanocrystalline bismuth ferrite by solution combustion route

2015 ◽  
Vol 9 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Kakali Sarkar ◽  
Soumya Mukherjee ◽  
Siddhartha Mukherjee
Keyword(s):  
Crystallite Size ◽  
Bismuth Ferrite ◽  
Structural Phase ◽  
Average Crystallite Size ◽  
Magnetic Behaviour ◽  
Solution Combustion ◽  
Chemical Route ◽  
Structural Formation ◽  
Xrd Diffraction ◽  
The Matrix

Multiferroic bismuth ferrite (BFO) and Ni-doped bismuth ferrites, with perovskite structure, were synthesized by chemical route at the temperatures ranging from 500 to 600 ?C in controlled atmosphere. The structural phase analysis of materials was identified by XRD and crystallite size was calculated from the half width measurement of the well defined major XRD diffraction peak. Average crystallite size was calculated by applying Scherrer?s formula and found to have values in the range from 14 to 35 nm. FESEM was used to evaluate the morphology and structural formation of nanocrystallite grains, while EDX confirmed elemental composition including the presence of dopant in the matrix. Dielectric properties and effect of electric field on polarization behaviour were studied for both undoped and Ni-doped BFO. Doping shows a clear change in ferroelectric behaviour. Antiferromagnetic nature of bulk bismuth ferrite transforms to superparamagnetic strong ferroelectric nature for both undoped and nickel doped nanocrystalline bismuth ferrite due to its close dimension of crystallite size with magnetic domains leading to break-down of frustrated spin cycloidal moment. The superparamagnetism behaviour is more pronounced for the nickel doped BFO though magnetic saturation is slightly higher for the undoped nanocrystalline bismuth ferrite.

Highly recyclable Ti0.97Ni0.03O1.97 catalyst coated on cordierite monolith for efficient transformation of arylboronic acids to phenols and reduction of 4-nitrophenol

2021 ◽  
Author(s):  
prasanna b ◽  
K M Usha ◽  
M. S. Hedge
Keyword(s):  
Crystallite Size ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
Arylboronic Acids ◽  
Tio2 Catalyst ◽  
Efficient Transformation

A stable Ni2+ substituted TiO2 catalyst (Ti0.97Ni0.03O1.97) has been synthesized by solution combustion method with an average crystallite size of 7.5 nm. Ti1-xNixO2-x (x = 0.01 - 0.06) crystallize in...

scholarly journals Formation of NanoscaleMg(x)Fe(1-x)O  (x=0.1,0.2,0.4)Structure by Solution Combustion: Effect of Fuel to Oxidizer Ratio

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Mohsen Ahmadipour ◽  
K. Venkateswara Rao ◽  
V. Rajendar
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Crystallite Size ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Particle Size And Morphology ◽  
Size And Morphology

Mg(x)Fe(1-x)O(magnesiowustite) nanopowder samples synthesized by solution-combustion method and fuel to oxidizer ratio (Ψ=1,1.25) are used as a control parameter to investigate how particle size and morphology vary withΨ. The method is inexpensive and efficient for synthesis of oxide nanoparticles. The average crystallite size ofMg(x)Fe(1-x)Onanoparticles was estimated from the full-width-half maximum of the X-ray diffraction peaks of powders using Debye-Scherrer’s formula; the average crystallite size varies from 16 nm to 51 nm. From X-ray diffraction analysis, it was observed thatMg(x)Fe(1-x)Onanoparticles have cubic structure. The particle size measured by particle size analyzer ranges from 37.7 nm to 73 nm which is in the order of XRD results. Thermal analysis was done by thermal gravimetric-differential thermal analyzer. The particle size and morphology of the synthesized powder were examined by transmission electron microscope and scanning electron microscope. The crystal size and particle size were compared with some of the most recently published research works by XRD and TEM. FTIR conforms formation of theMg(x)Fe(1-x)O.

Tuning of Magnetic Properties in Cobalt-Doped Nanocrystalline Bismuth Ferrite

2011 ◽  
Vol 1368 ◽  
Author(s):  
Gina Montes Albino ◽  
Oscar Perales-Pérez ◽  
Boris Renteria ◽  
Marco Galvez ◽  
Maxime J-F Guinel
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Crystallite Size ◽  
Bismuth Ferrite ◽  
Average Crystallite Size ◽  
Fine Tuning ◽  
Free Standing ◽  
Cobalt Ions ◽  
Polyol Medium ◽  
Co Doped

ABSTRACTThis study reports on the structural and magnetic characterizations of free-standing bismuth ferrite, BiFeO3, nanoparticles synthesized in polyol medium. Fine tuning of the ferrite magnetic properties was achieved by adding an excess bismuth species or doping with cobalt ions, coupled with thermal annealing. Crystalline Bi1-yCoyFeO3 powders (where ‘y’ ranges from 0.00 to 0.10) were produced after annealing the precursors for one hour at 700οC. The average crystallite size was calculated to be approximately 22 nm. We found that the synthesis under stoichiometric excess of Bi species (up to 10 at.%) promoted a more complete crystallization of the material, i.e., no precursor phases remained. Furthermore, both the saturation magnetization and the coercivity of the synthesized powders were strongly influenced by the concentration of Co. They increased from 0.13 emu/g and 19 Oe to 3.5 emu/g and 1183 Oe for pure BiFeO3 and 10 at.% Co-doped BiFeO3, respectively.

scholarly journals Thermally driven structural phase transformation and dislocation density of CdS nanoparticles precipitated without surfactant in KOH alkaline medium

2021 ◽  
Author(s):  
Chan Kok Sheng ◽  
◽  
Yousef Mohammad Alrababah ◽  
Keyword(s):  
Dislocation Density ◽  
Crystallite Size ◽  
Alkaline Medium ◽  
Annealing Temperature ◽  
Elevated Temperatures ◽  
Structural Phase ◽  
Average Crystallite Size ◽  
Morphological Properties ◽  
Cds Nanoparticles ◽  
Vibration Band

The present research demonstrates a detailed discussion for the effect of annealing temperature on the structural transformation and surface morphology of the CdS nanoparticles synthesized using the precipitation method without surfactant in KOH alkaline medium. The annealing temperature used was in the range of 160 – 480 oC. The samples structural, functional group and morphological properties were investigated by using XRD, FTIR and SEM techniques. XRD analysis reveals that the CdS has gradually been transformed from the pure cubic to hexagonal polycrystalline structure as well as improved crystallinity upon increasing the temperature. Besides, the parameters of average crystallite size and dislocation density were calculated using the established Debye- Scherrer equation. The average crystallite size was in nano-dimension and increases gradually with temperature. The FTIR spectra indicate that the characteristic vibration band of CdS emerged in the lower wavenumber region of 650 and 500 cm-1, and the band becomes stronger as the temperature rises. Also, the SEM images demonstrate that the CdS exhibits uniform spherical morphology and the particle size grows larger at elevated temperatures. The improved crystallinity and structural properties tuning ability against temperature allows beneficial optical applications as solar cells, photocatalysts, non-linear optics, light emitting diodes and optoelectronic devices.

scholarly journals Fabrication and characterization of nanostructured Ba-doped BiFeO3 porous ceramics

2016 ◽  
Vol 34 (1) ◽  
pp. 148-156 ◽  
Author(s):  
E. Mostafavi ◽  
A. Ataie
Keyword(s):  
Grain Size ◽  
Bismuth Ferrite ◽  
Porous Ceramic ◽  
Structural Phase ◽  
Porous Ceramics ◽  
X Ray Diffraction ◽  
Pore Former ◽  
Compact Sample ◽  
Mean Grain Size ◽  
The Matrix

AbstractNanostructured barium doped bismuth ferrite, Bi₀.₈Ba₀.₂FeO₃ porous ceramics with a relatively high magnetic coercivity was fabricated via sacrificial pore former method. X-ray diffraction results showed that 20 wt.% Ba doping induces a structural phase transition from rhombohedral to distorted pseudo-cubic structure in the final porous samples. Moreover, utilizing Bi₀.₈Ba₀.₂FeO₃ as the starting powder reduces the destructive interactions between the matrix phase and pore former, leading to an increase in stability of bismuth ferrite phase in the final porous ceramics. Urea-derived Bi₀.₈Ba₀.₂FeO₃ porous ceramic exhibits density of 4.74 g/cm³ and porosity of 45 % owing the uniform distribution of interconnected pores with a mean pore size of 7.5 μm. Well defined nanostructured cell walls with a mean grain size of 90 nm were observed in the above sample, which is in a good accordance with the grain size obtained from BET measurements. Saturation magnetization decreased from 2.31 in the Bi₀.₈Ba₀.₂FeO₃ compact sample to 1.85 A m²/kg in urea-derived Bi₀.₈Ba₀.₂FeO₃ porous sample; moreover, coercivity increased from 284 to 380 kA/m.

Influence of Preparation Temperature on Performance of Ce1-xPrxO2 Ultrafine Powder Prepared by a Microemulsion Process

2008 ◽  
Vol 368-372 ◽  
pp. 784-786 ◽  
Author(s):  
Jun Yang ◽  
Zhen Feng Zhu ◽  
Jing Ping Li
Keyword(s):  
Crystallite Size ◽  
Calcination Temperature ◽  
Average Crystallite Size ◽  
Ultrafine Powder ◽  
Microemulsion System ◽  
Sem Images ◽  
Preparation Temperature ◽  
Annealing Conditions

A W/O microemulsion system composed of OP-emolsifier / water / cyclohexane / 1-Pentanol was adopted to prepare ultrafine Ce1-xPrxO2 powder via the reaction between the precipitants of cerium and praseodymium salt solved in the nano reactors. The influence of the annealing conditions on the preparation of Ce1-xPrxO2 powder was investigated. It was shown that, with the increase of calcination temperature from 400 °C to 800 °C, the average crystallite size of the particles increases from 9.5 nm to 25.8 nm. FE-SEM images showed that shape of the particles is layered and sheet-like.

The Effect of Different Methods to Pretreat Reed Pulp on the Crystallinity of Microcrystalline Cellulose

2014 ◽  
Vol 1056 ◽  
pp. 12-15 ◽  
Author(s):  
Wen Long Zhang ◽  
Wen Long Zhao ◽  
Ya Jie Dai
Keyword(s):  
Crystallite Size ◽  
Microcrystalline Cellulose ◽  
Average Crystallite Size ◽  
Comprehensive Analysis ◽  
Raw Material ◽  
Type I ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimethyl Acetamide ◽  
Crystal Type

Reed Pulp was Raw Material that Pretreated by Four Methods {ultrasonic, Microwave, N, N-Dimethyl Acetamide (DMAc) and Tetrahydrofuran (THF)}. Reed Microcrystalline Cellulose (MCC) was Prepared by the Dilute Hydrochloric Acid Hydrolysis from Pretreated Reed Pulp. the Influences of Pretreatment Methods on Crystalline Type, Crystallinity and Crystallite Size of MCC were Investigated by X-Ray Diffraction (XRD). the Results Showed that the Crystallinity of MCC with Four Pretreatment Methods was 68.45%, 62.28%, 63.21% and 69.56%, Respectively. the Average Crystallite Size of MCC Prepared by Hydrolysis after Pretreated by Dmac was the Largest. whereas, the Crystal Type of MCC was Not Changed, it was still the Cellulose Type I. Comprehensive Analysis Indicated that the Effects of MCC Prepared by Hydrolysis after Pretreated by Ultrasonic were the Best.

scholarly journals Preparation and Mechanical Properties of Graphene Oxide: Cement Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fakhim Babak ◽  
Hassani Abolfazl ◽  
Rashidi Alimorad ◽  
Ghodousi Parviz
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Cement Composites ◽  
Xrd Diffraction ◽  
Calcium Silicate Hydrates ◽  
The Matrix ◽  
Scanning Electron

We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

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