Structural and Magnetic Characterization of LaFe1-xAlxO3 (x = 0 and 0.2) Orthoferrites Synthesized by Gelatin Method

2017 ◽  
Vol 899 ◽  
pp. 227-231 ◽  
Author(s):  
Patrícia Mendonça Pimentel ◽  
J.L.S. Dutra ◽  
A.C. Lima ◽  
J.H. Araújo ◽  
Osmar Bagnato ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Treatment Temperature ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Magnetic Characterization ◽  
Organic Precursor ◽  
Transmission Electron ◽  
Heat Treated ◽  
Xrd Patterns

The rare-earth orthoferrites (LnFeO3) are promising materials for various applications, such as chemical sensors, cathode for SOFC, catalysts, among others. In general, these oxides are synthesized at temperatures higher than 700 °C. In this work, nanocrystalline LaFe1-xAlxO3 (x=0, x=0.2) powders were synthesized by a method that uses gelatin as organic precursor and heat treated at 400, 600 and 800 °C. The structural and magnetic characterization of powders was carried out by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Morphological analysis was performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD patterns revealed the formation of orthoferrites single phase since 400°C. The powders exhibited weak ferromagnetic behavior at room temperature where the values of saturation magnetization, remanence and coercivity varied with the doping and heat treatment temperature.

Synthesis and Characterization of a New Amino-Functionalized PMO Material

2013 ◽  
Vol 712-715 ◽  
pp. 271-279
Author(s):  
Fei Ding ◽  
Shuang Xi Liu
Keyword(s):  
Electron Microscopy ◽  
Solid State Nmr ◽  
Alkyl Chain ◽  
Reaction System ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Xrd Patterns

A new organic silicane which is bridged by a long amino-functionalized alkyl chain was prepared and used as the precursor in the synthesis of a series of PMO materials. The organic silicane was added into the reaction system in CH2Cl2and the PMO materials were prepared by a simple stirring method under acidic condition, with a nonionic surfactantBrij 76 as template. To find the proper synthesis condition, the time of stirring and the proportion of organic silicane and TEOS were varied. Liquid and solid state NMR, X-ray diffraction (XRD) patterns, thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and N2-physisorption properties were used to characterize the structures.

scholarly journals Synthesis and Characterization of Birnessite and Cryptomelane Nanostructures in Presence of Hoffmeister Anions

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Marcos A. Cheney ◽  
Robin Jose ◽  
Arghya Banerjee ◽  
Pradip K. Bhowmik ◽  
Shizhi Qian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Manganese Dioxide ◽  
Chloride Ion ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Transmission Electron ◽  
Xrd Patterns

The effect of Hoffmeister anions , , and on the structure and morphology of birnessite and cryptomelane-type manganese dioxide nanostructures, produced by the reduction reaction of and in aqueous acidic media, was studied. The syntheses were based on the decomposition of aqueous in presence of HCl for birnessite-type and acidified for cryptomelane-type manganese dioxide under soft hydrothermal conditions. They were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. XRD patterns show the formation of birnessite for the first synthesis and a mixture of cryptomelane and birnessite-types for the second synthesis. XRD data revealed that the Hoffmeister anions have a significant effect on the nanostructures of birnessite. The sulphate ion-treated birnessite has the smallest crystals, whereas the chloride ion-treated birnessite has the largest crystals. Their TEM and HRTEM studies revealed a transformation from nanoplatelet morphology for chloride-treated samples to nanofibrous morphology for sulphate-treated birnessite. For the cryptomelane nanostructures, Hoffmeister anions also show a profound effect on their crystalline structures as determined by XRD analyses revealing a transformation of the cryptomelane phase to birnessite phase of . This transformation is also supported by TEM and HRTEM studies.

scholarly journals Solvent-Free Mechanochemical Synthesis and Characterization of Nickel Tellurides with Various Stoichiometries: NiTe, NiTe2 and Ni2Te3

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1959
Author(s):  
Matjaž Kristl ◽  
Sašo Gyergyek ◽  
Srečo D. Škapin ◽  
Janja Kristl
Keyword(s):  
Electron Microscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Energy Consuming ◽  
Tga And Dsc

The paper reports the synthesis of nickel tellurides via a mechanochemical method from elemental precursors. NiTe, NiTe2, and Ni2Te3 were prepared by milling in stainless steel vials under nitrogen, using milling times from 1 h to 12 h. The products were characterized by powder X-ray diffraction (pXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), UV-VIS spectrometry, and thermal analysis (TGA and DSC). The products were obtained in the form of aggregates, several hundreds of nanometers in size, consisting of smaller nanosized crystallites. The magnetic measurements revealed a ferromagnetic behavior at room temperature. The band gap energies calculated using Tauc plots for NiTe, NiTe2, and Ni2Te3 were 3.59, 3.94, and 3.70 eV, respectively. The mechanochemical process has proved to be a simple and successful method for the preparation of binary nickel tellurides, avoiding the use of solvents, toxic precursors, and energy-consuming reaction conditions.

scholarly journals Effect of Different Mediated Agents on Morphology and Crystallinity of Synthesized Silver Nanowires Prepared by Polyol Process

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Mohammad Taghi Satoungar ◽  
Hamed Azizi ◽  
Saeid Fattahi ◽  
Mohammad Khajeh Mehrizi ◽  
Hedieh Fallahi
Keyword(s):  
Electron Microscopy ◽  
Silver Nanowires ◽  
Vinyl Pyrrolidone ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Solution Field ◽  
Poly Vinyl Pyrrolidone ◽  
Xrd Patterns ◽  
Structural Characterizations

Synthesis and characterization of multiple crystalline silver nanowires (NWs) with uniform diameters were carried out by using 1,2-propandiol and ethylene glycol (EG) as comediated solvents and FeCl3as mediated agent in the presence of poly(vinyl pyrrolidone) (PVP). Experimental data and structural characterizations revealed that AgNWs have evolved from the multiple crystalline seeds initially generated by reduction of AgNO3with EG and 1,2-propandiol followed by reducing Fe(III) to Fe(II) which in turn reacts with and removes adsorbed atomic oxygen from the surfaces of silver seeds. In addition, uniform silver nanowires were obtained by using FeCl2and AlCl3as mediated agents in EG solution. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed uniform nanowires in both diameter and length. UV-Vis spectra showed adsorption peaks confirming the formation of nanowires. X-ray diffraction (XRD) patterns displayed the final product with high crystallinity and purity. In this study, a growth mechanism for forming AgNWs was proposed and a comparison between different mediated agents was carried out.

Synthesis and Characterization of Si3N4 Nanopowder by RF Induction Thermal Plasma

2017 ◽  
Vol 898 ◽  
pp. 1597-1602 ◽  
Author(s):  
Xuan Zhao ◽  
Hai Yan Chen ◽  
Chen Yang Shu ◽  
Li Hua Dong ◽  
Yan Sheng Yin
Keyword(s):  
Electron Microscopy ◽  
Thermal Plasma ◽  
X Ray Diffraction ◽  
N Source ◽  
Α Phase ◽  
Induction Thermal Plasma ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures

Nano-Si3N4 has been synthesized by the thermal plasma with silicon tetrachloride (SiCl4) as the Si source, liquid ammonia (NH3) as the N source, and silane (SiH4) as the catalyst. And the prepared Nano-Si3N4was heat-treated atfour different temperatures of 1350°C, 1400°C, 1450°C, 1500°C. The as-prepared samples were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). The results showed that the particle size of the nano-Si3N4 powder was less than 100 nm and it was amorphous when the temperature below 1450°C. At 1500°C, the synthesized Si3N4 powder with the grain size of 10 nm was crystallized, and the α-phase Si3N4 reached more than 90%.

Growth and Characterization of Well-Aligned RuO2/R-TiO2 Heteronanostructures on Sapphire (100) Substrates by Reactive Magnetron Sputtering

2011 ◽  
Vol 170 ◽  
pp. 78-82
Author(s):  
Hung Pin Hsu ◽  
Ying Sheng Huang ◽  
Chien Nan Yeh ◽  
Yi Min Chen ◽  
Dah Shyang Tsai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Magnetron Sputtering ◽  
Reactive Magnetron Sputtering ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vertically Aligned ◽  
Xrd Patterns ◽  
Electron Diffractometry

We report the growth of well-aligned RuO2/R-TiO2 heteronanostructures on sapphire (100) substrates by reactive magnetron sputtering using Ti and Ru metal targets under different conditions. The surface morphology and structural properties of the as-deposited heteronanostructures were characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected-area electron diffractometry (SAED). The FESEM micrographs and XRD patterns indicated the growth of vertically aligned RuO2(001) nanotubes and twinned V-shaped RuO2(101) nanowedges (NWs) on top of R-TiO2 nanorods under different sputtering pressures. TEM and SAED characterizations of the V-shaped RuO2 NWs showed that the NWs are crystalline RuO2 with twin planes of (101) and twin direction of [ 01] at the V-junction.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

scholarly journals Fabrication and Physical Properties of Single-Crystalline Βeta-FeSi2 Nanowires

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Chih-Yung Yang ◽  
Shu-Meng Yang ◽  
Yu-Yang Chen ◽  
Kuo-Chang Lu
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Field Emitters ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Carrier Gases

Abstract In this study, self-catalyzed β-FeSi2 nanowires, having been wanted but seldom achieved in a furnace, were synthesized via chemical vapor deposition method where the fabrication of β-FeSi2 nanowires occurred on Si (100) substrates through the decomposition of the single-source precursor of anhydrous FeCl3 powders at 750–950 °C. We carefully varied temperatures, duration time, and the flow rates of carrier gases to control and investigate the growth of the nanowires. The morphology of the β-FeSi2 nanowires was observed with scanning electron microscopy (SEM), while the structure of them was analyzed with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The growth mechanism has been proposed and the physical properties of the iron disilicide nanowires were measured as well. In terms of the magnetization of β-FeSi2, nanowires were found to be different from bulk and thin film; additionally, longer β-FeSi2 nanowires possessed better magnetic properties, showing the room-temperature ferromagnetic behavior. Field emission measurements demonstrate that β-FeSi2 nanowires can be applied in field emitters.

Hydrothermal Synthesis and Characterization of BiFeO3 Polyhedral Crystallites

2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.

Effect of hydrothermal dwell time on the diameter-controlled synthesis and magnetic property of MnO2 nanorods

2014 ◽  
Vol 28 (06) ◽  
pp. 1450045 ◽  
Author(s):  
Arbab Mohammad Toufiq ◽  
Fengping Wang ◽  
Qurat-ul-Ain Javed ◽  
Yan Li
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Dwell Time ◽  
Hydrothermal Reaction ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Transmission Electron ◽  
Facile Hydrothermal Route ◽  
Hydrothermal Reaction Time

In this paper, single crystalline 1D tetragonal MnO 2 pen-type nanorods were synthesized by varying the dwell time through a facile hydrothermal route at a reaction temperature of 250°C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the diameter of MnO 2 nanorods decreases from 460 nm to 250 nm with the increase in hydrothermal reaction time from 5 h to 15 h. Field-emission scanning electron microscopy (FESEM) and TEM studies revealed the evolution of improved surface morphology of MnO 2 nanorods that are prepared with longer hydrothermal reaction time. The magnetic properties of the products were evaluated using vibrating sample magnetometer (VSM) at room temperature, which showed that the as-prepared samples exhibit weak ferromagnetic behavior. The effect of diameter on the magnetization values was observed and discussed in detail.

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