scholarly journals Suppression of the Cycloidal Spin Arrangement in BiFeO3 Caused by the Mechanically Induced Structural Distortion and Its Effect on Magnetism

2021 ◽  
Vol 8 ◽  
Author(s):  
Klebson Lucenildo Da Silva ◽  
Rafael Santiago Trautwein ◽  
Rodolfo Bezerra Da Silva ◽  
Martin Fabián ◽  
Erik Čižmár ◽  
...  
Keyword(s):  
Bismuth Ferrite ◽  
Spectral Component ◽  
Average Particle Size ◽  
Chemical Properties ◽  
Magnetic Behavior ◽  
Structural Features ◽  
Ferromagnetic Behavior ◽  
Average Particle ◽  
X Ray ◽  
Spin Arrangement

Bismuth ferrite (BiFeO3) particles are prepared by a combined mechanochemical−thermal processing of a Bi2O3 + α-Fe2O3 mixture. Structural, magnetic, hyperfine, morphological and chemical properties of the as-prepared BiFeO3 are studied using X-ray diffraction (Rietveld refinement), 57Fe Mössbauer spectroscopy, SQUID magnetometry, electron microscopy and energy dispersive X-ray spectroscopy. It is revealed that the structure of the ferrite exhibits the long-range distortion (significantly tilted FeO6 octahedra) and the short-range disorder (deformed FeO6 octahedra). Consequently, these structural features result in the suppression of a space modulated cycloidal spin arrangement in the material. The latter manifests itself by the appearance of only single spectral component in the 57Fe Mössbauer spectrum of BiFeO3. The macroscopic magnetic behavior of the material is interpreted as a superposition of ferromagnetic and antiferromagnetic contributions with a large coercive field and remanent magnetization. Taking into account the average particle size of the as-prepared BiFeO3 particles (∼98 nm), exceeding the typical period length of cycloid (∼62 nm), both the suppression of the spiral spin structure in the material and its partly ferromagnetic behavior are attributed to the crystal lattice distortion caused by mechanical stress during the preparation procedure.

Structural, Dielectric and Magnetic Properties of Bi2Fe4O9 Thin Film by RF Magnetron Sputtering

2015 ◽  
Vol 14 (05n06) ◽  
pp. 1550024
Author(s):  
M. Santhiya ◽  
K. S. Pugazhvadivu ◽  
K. Tamilarasan
Keyword(s):  
Thin Film ◽  
Bismuth Ferrite ◽  
Magnetic Behavior ◽  
Rf Magnetron Sputtering ◽  
Dielectric Behavior ◽  
Ferromagnetic Behavior ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray

This paper presents the growth of bismuth ferrite ( Bi 2 Fe 4 O 9) thin film by radio frequency magnetron reactive sputtering on p- Si (100) substrate and the characterization of the grown thin film. The deposited thin film is characterized by X-ray diffraction (XRD), field emission scanning electron micrograph (FESEM), energy dispersive X-ray analysis (EDAX), dielectric measurements and vibrating sample magnetometer (VSM) analysis. The XRD study reveals the orthorhombic structure of the crystallites and the particle size is calculated as 45 nm. The FESEM result confirms that the film has smooth surface and uniform distribution of nanoclusters. The percentage of chemical compositions of the film is confirmed by EDAX measurement. The dielectric behavior of the film is examined in terms of the dielectric constant and the dielectric loss as a function of frequency. The magnetic behavior of the film is measured using VSM with the applied magnetic field of about 1 Tesla and the result shows the ferromagnetic behavior of the sample at room temperature.

scholarly journals Photodegradation of Eosin Y Using Silver-Doped Magnetic Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Eman Alzahrani
Keyword(s):  
Magnetic Nanoparticles ◽  
Irradiation Time ◽  
Average Particle Size ◽  
Chemical Properties ◽  
Xrd Analysis ◽  
Order Rate Constant ◽  
Average Particle ◽  
Eosin Y ◽  
Human Beings ◽  
X Ray

The purification of industrial wastewater from dyes is becoming increasingly important since they are toxic or carcinogenic to human beings. Nanomaterials have been receiving significant attention due to their unique physical and chemical properties compared with their larger-size counterparts. The aim of the present investigation was to fabricate magnetic nanoparticles (MNPs) using a coprecipitation method, followed by coating with silver (Ag) in order to enhance the photocatalytic activity of the MNPs by loading metal onto them. The fabricated magnetic nanoparticles coated with Ag were characterised using different instruments such as a scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDAX) spectroscopy, and X-ray diffraction (XRD) analysis. The average size of the magnetic nanoparticles had a mean diameter of about 48 nm, and the average particle size changed to 55 nm after doping. The fabricated Ag-doped magnetic nanoparticles were used for the degradation of eosin Y under UV-lamp irradiation. The experimental results revealed that the use of fabricated magnetic nanoparticles coated with Ag can be considered as reliable methods for the removal of eosin Y since the slope of evaluation of pseudo-first-order rate constant from the slope of the plot betweenln⁡(Co/C)and the irradiation time was found to be linear. Ag-Fe3O4nanoparticles would be considered an efficient photocatalyst to degrade textile dyes avoiding the tedious filtration step.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

scholarly journals Commercial Cokes and Graphites as Anode Materials for Lithium - Ion Cells

1997 ◽  
Vol 496 ◽  
Author(s):  
David J. Derwin ◽  
Kim Kinoshita ◽  
Tri D. Tran ◽  
Peter Zaleski
Keyword(s):  
Electron Microscopy ◽  
Ethylene Carbonate ◽  
Average Particle Size ◽  
Chemical Properties ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Bet Surface Area ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
Wide Range

AbstractSeveral types of carbonaceous materials from Superior Graphite Co. were investigated for lithium ion intercalation. These commercially available cokes, graphitized cokes and graphites have a wide range of physical and chemical properties. The coke materials were investigated in propylene carbonate based electrolytes and the graphitic materials were studied in ethylene carbonate / dimethyl solutions to prevent exfoliation. The reversible capacities of disordered cokes are below 230 mAh / g and those for many highly ordered synthetic (artificial) and natural graphites approached 372 mAh / g (LiC6). The irreversible capacity losses vary between 15 to as much as 200 % of reversible capacities for various types of carbon. Heat treated cokes with the average particle size of 10 microns showed marked improvements in reversible capacity for lithium intercalation. The electrochemical characteristics are correlated with data obtained from scanning electron microscopy (SEM), high resolution transmission electron microscopy (TAM), X - ray diffraction (XRD) and BET surface area analysis. The electrochemical performance, availability, cost and manufacturability of these commercial carbons will be discussed.

Fabrication of monoclinic BiVO4 photocatalyst film and its photocatalytic activity for organic pollutant removal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saranyoo Chaiwichian ◽  
Buagun Samran
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Average Particle Size ◽  
Pollutant Removal ◽  
Light Irradiation ◽  
Average Particle ◽  
Film Sample ◽  
Acid Orange 7 ◽  
Acid Orange ◽  
X Ray

Abstract Monoclinic BiVO4 photocatalyst films decorated on glass substrates were successfully fabricated via a dip-coating technique with different annealing temperatures of 400 °C, 450 °C, 500°C, and 550 °C. All of the physical and chemical properties of as-prepared BiVO4 photocatalyst film samples were investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectra techniques. The results revealed that the as-prepared BiVO4 photocatalyst film samples retained a monoclinic phase with an average particle size of about 50 – 100 nm. Moreover, the BiVO4 photocatalyst film samples showed a strong photoabsorption edge in the range of visible light with the band gap energy of 2.46 eV. The photocatalytic activities of all the film samples were tested by the degradation of model acid orange 7 under visible light irradiation. The BiVO4 photocatalyst film sample annealed at a temperature of 500 °C showed the highest photoactivity efficiency compared with other film samples, reaching up to 51%within 180 min. In addition, the stability and reusability of BiVO4 photocatalyst film sample made with an annealing temperature of 500 °C did not show loss of photodegradation efficiency of acid orange 7 after ten recycles. A likely mechanism of the photocatalytic process was established by trapping experiments, indicating that the hydroxyl radical scavenger species can be considered to play a key role for acid orange 7 degradation under visible light irradiation.

Nanocrystalline α-Fe2O3: A Superparamagnetic Material for w-LED Application and Waste Water Treatment

2021 ◽  
Author(s):  
Mahesh Gaidhane ◽  
Deepak Taikar ◽  
Pravin Gaidhane ◽  
Kalpana Nagde
Keyword(s):  
Photocatalytic Activity ◽  
Waste Water Treatment ◽  
Sol Gel ◽  
Average Particle Size ◽  
Emission Spectra ◽  
Broad Emission Band ◽  
Average Particle ◽  
X Ray ◽  
Prepared Material ◽  
Cie Chromaticity

Abstract Nanocrystalline α-Fe2O3 is synthesized by sol-gel technique. The prepared nanomaterial was characterized by X-ray diffraction (XRD), SEM, TEM, Fourier Transform Infrared (FTIR) spectroscopy, Vibrating Sample Magnetometry (VSM) and photoluminescence (PL) techniques. X-ray powder diffraction analysis confirmed the formation of α-Fe2O3. Electron microscopy showed spherical morphologies with an average particle size of 30-40 nm. The magnetic property of the prepared material was studied by VSM at room temperature. VSM study shows superparamagnetic nature of the synthesized nanoparticles. Photoluminescence (PL) emission spectra show intense broad emission band centered at 570 nm with 393 nm excitation indicating its usefulness for w-LED application. The CIE-chromaticity color coordinates of prepared material were calculated. The photocatalytic activity of the α-Fe2O3 nanoparticles was analyzed and the nanopowder exhibited good photocatalytic activity for the removal AO7 from its aqueous solution.

scholarly journals Synthesis of cuprous oxide nanocubes combined with chitosan nanoparticles and its application to p-nitrophenol degradation

2021 ◽  
Vol 22 (48) ◽  
Author(s):  
Tran Thi Bich Quyen ◽  
Ngo Nguyen Tra My ◽  
Do Thi Thuy Ngan ◽  
Duy Toan Pham ◽  
Doan Van Hong Thien
Keyword(s):  
Photocatalytic Activity ◽  
Cuprous Oxide ◽  
Treatment Time ◽  
Average Particle Size ◽  
Chitosan Nanoparticles ◽  
Synthetic Approach ◽  
Average Particle ◽  
X Ray ◽  
Nitrophenol Reduction ◽  
Nitrophenol Degradation

For the first time, cuprous oxide nanocubes (Cu2O NCBs) were successfully combined with chitosan nanoparticles (CS NPs) to generate Cu2O NCBs/CS NPs composites material with highly optical property and photocatalytic activity using a simple and eco-friendly synthetic approach at room temperature for 30 min. The synthesized Cu2O NCBs NPs/CS NPs were determined characterizations by Ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X – ray Diffraction (XRD),  Transmission Electron Microscope (TEM) and Energy-dispersive X-ray spectroscopy (EDX). Results show that the Cu2O NCBs/CS NPs composites have an average particle size of ~3-5 nm; in which, Cu2O has the form of nanocubes (Cu2O NCBs) with size ~3-4 nm and chitosan nanoparticles with spherical shape (CS NPs) with size ~4-5 nm. In addition, the percent (%) composition of elements present in Cu2O NCBs/CS NPs composites material have been obtained respective: Cu (23.99%), O (38.18%), and C (33.61%). Moreover, Cu2O NCBs/CS NPs composites material was also investigated for photocatalytic activity applied in p-nitrophenol degradation. The obtained results showed that the catalytic capability of Cu2O NCBs/CS NPs for p-nitrophenol reduction reached the highest efficiency >55% in the treatment time of 25 min, and this efficiency was higher than that result of using ZnO@chitosan nanoparticles (ZnO@CS NPs) catalyst under the same conditions for comparison.

scholarly journals FORMULATION AND EVALUATION OF DOXORUBICIN CONTAINING NANOGELS FOR DELIVERY TO CANCER CELLS

2018 ◽  
Vol 8 (5) ◽  
pp. 178-183
Author(s):  
Manish Kumar ◽  
Hemant K. Sharma
Keyword(s):  
Average Particle Size ◽  
Gellan Gum ◽  
Cross Linking ◽  
Average Particle ◽  
Scanning Calorimetry ◽  
Green Method ◽  
X Ray ◽  
Oppositely Charged ◽  
Chemical Cross Linking

The objective of this study is to prepare nanogels were prepared via charged gellan gum. It was prepared by in situ cross linking reaction between two oppositely charged materials by green method without use of chemical cross linking agents. The prepared nanogels were characterized by Dynamic light scattering, scanning electron microscopy, differential scanning calorimetry and X- Ray diffractometry. The prepared formulation had average particle size of 226 nm with polydispersity index of 0.3. The doxorubicin loaded nanogel demonstrated sustained release for 20 h. The prepared nanogels were hemocompatible and cyctocompatible as revealed by hemocompatibility and MTT assay respectively. All results confirmed that these nanogels can be used for cancer treatment. Keywords: Nanogel, Chitosan, Gellan gum, Doxorubicin, Cancer.

scholarly journals Textiles Printing Using Microencapsulated Pigments in Biodegradable Thickeners

2018 ◽  
Vol 15 (1) ◽  
pp. 6122-6129 ◽  
Author(s):  
Meram S. Abdelrahman ◽  
Sahar Nassar ◽  
Hamada Mashaly ◽  
Safia Mahmoud ◽  
Dalia Maamoun
Keyword(s):  
Screen Printing ◽  
Average Particle Size ◽  
Morphological Structure ◽  
Core Material ◽  
Average Particle ◽  
X Ray ◽  
Screen Printing Technique ◽  
Printing Technique ◽  
Encapsulation Process ◽  
Dispersing Agents

Micro-encapsulated pigments were formulated into biodegradable printing pastes and their properties were analyzed. The pigment was used as the core material and polylactic-based biodegradable thickener was used as the wall-former. Cotton/polyester blend fabric was printed with micro-encapsulated pigment using screen-printing technique without dispersing agents, penetrating agents, leveling agents or other auxiliaries. Micro-encapsulated pigment has been characterized in terms of average particle size and size distribution, morphological structure and elemental composition using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The variations in viscosity and paste stability were observed upon storing over 7 days at ambient temperature. For permanence, the micro-encapsulation process afforded better colorfastness properties against light, washing, rubbing, and perspiration.

scholarly journals Photoluminescences properties of lanthanum-silver co-doped ZnO nano particles

2018 ◽  
Vol 4 (4) ◽  
pp. 135-141 ◽  
Author(s):  
V. Porkalai ◽  
B. Sathya ◽  
D. Benny Anburaj ◽  
G Nedunchezhian ◽  
S. Joshua Gnanamuthu ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Zinc Acetate Dihydrate ◽  
Average Particle Size ◽  
Semiconductor Nanoparticles ◽  
Nano Particles ◽  
Average Particle ◽  
Rare Earth Ion ◽  
X Ray ◽  
Doped Zno ◽  
Co Doped

Recently, transition metal (TM) and rare earth ion doped II–VI semiconductor nanoparticles have received much attention because such doping can modify and improve optical properties of II–VI semiconductor nanoparticles by large amount. In this study, undoped, La doped and La+Ag co-doped ZnO nano particles have been successfully synthesized by sol-gel method using the mixture of Zinc acetate dihydrate and ethanol solution. The powders were calcinated at 600 °C for 2 h. The effect of lanthanum and lanthanum-silver incorporation on the structure, morphology, optical and electrical conductivity were examined by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Absorption (EDAX), Fourier transform infrared spectroscopy (FTIR), UV and Photo Luminescence (PL) Characterization. The average particle size of the synthesized ZnO nanoparticles is calculated using the Scherrer formula and is found to be of less than 20 nm. Luminescences properties were found to be enhanced for the La and La+Ag co-doped ZnO nanoparticles.

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