scholarly journals Hyperfine interaction and some thermomagnetic properties of amorphous and partially crystallized Fe70−xMxMo5Cr4Nb6B15 (M = Co or Ni, x = 0 or 10) alloys

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 121-126
Author(s):  
Jakub Rzącki ◽  
Jan Świerczek ◽  
Mariusz Hasiak ◽  
Jacek Olszewski ◽  
Józef Zbroszczyk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hyperfine Interaction ◽  
Magnetic Structure ◽  
Curie Point ◽  
Room Temperature ◽  
Ferromagnetic Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Thermomagnetic Properties

Abstract As revealed by Mössbauer spectroscopy, replacement of 10 at.% of iron in the amorphous Fe70Mo5Cr4Nb6B15 alloy by cobalt or nickel has no effect on the magnetic structure in the vicinity of room temperature, although the Curie point moves from 190 K towards ambient one. In the early stages of crystallization, the paramagnetic crystalline Cr12Fe36Mo10 phase appears before α-Fe or α-FeCo are formed, as is confirmed by X-ray diffractometry and transmission electron microscopy. Creation of the crystalline Cr12Fe36Mo10 phase is accompanied by the amorphous ferromagnetic phase formation at the expense of amorphous paramagnetic one.

DIELECTRIC PROPERTIES OF ULTRAFINE Zn-DOPED CaCu3Ti4O12 CERAMIC

2012 ◽  
Vol 02 (01) ◽  
pp. 1250007 ◽  
Author(s):  
LAXMAN SINGH ◽  
U. S. RAI ◽  
K. D. MANDAL ◽  
MADHU YASHPAL
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sintered Powder

Ultrafine powder of CaCu2.80Zn0.20Ti4O12 ceramic was prepared using a novel semi-wet method. DTA/TG analysis of dry powder gives pre-information about formation of final product around 800°C. The formation of single phase was confirmed by X-ray diffraction analysis. The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm, respectively. Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic. Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.

Luminescence from SiOx Nanoclusters

1994 ◽  
Vol 358 ◽  
Author(s):  
Paul wickboldt ◽  
Hyeonsik M. Cheong ◽  
Dawen Pang ◽  
Joseph H. Chen ◽  
William paul
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cluster Size ◽  
Radiative Recombination ◽  
Room Temperature ◽  
Broad Band ◽  
Infrared Transmission ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Transmission Electron

ABSTRACTSiOx nanoclusters (7 nm to 17 nm) are produced by evaporation of SiO (or Si) in Ar (+O2) atmospheres. Room temperature photoluminescence (PL) measurements in vacuum reveal a broad band centered at 1.65 eV. Upon exposure to gas this PL band is extinguished in a matter of seconds, and another band centered at 2.12 eV appears. This effect occurs regardless of the gas used (He, Ar, N2, O2, H2O vapor or air) and is entirely reversible upon evacuation.Transmission electron microscopy (TEM), Raman, infrared transmission, and X-ray photoluminescence spectroscopy (XPS) measurements are used to characterize the clusters. They are noncrystalline, and the oxidation state is a suboxide rather than SiO2 The PL spectra are independent of cluster size. The PL does not occur without sufficient oxidation and does not require the presence of bonded hydrogen. We are led to speculate that the radiative recombination occurs in electron states derived from a suboxide.

Design of 2D-nanocrystals in water: preparation, structure and functionalization

2018 ◽  
Vol 90 (5) ◽  
pp. 833-844
Author(s):  
Leonid Aslanov ◽  
Valery Zakharov ◽  
Ksenia Paseshnichenko ◽  
Aleksandr Yatsenko ◽  
Andrey Orekhov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
High Resolution ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Room Temperature ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron

AbstractA new method for synthesis of 2D nanocrystals in water was proposed. The use of perfluorothiophenolate ions as surfactant allowed us to produce 2D single-crystal nanosheets of CaS at pH=9 and flat nanocrystals of PbS at pH=9 at room temperature. Mesocrystalline nanobelts of CdS and mesocrystals of PbS were obtained at pH=3–5 and pH=10–12, respectively. Morphology, structure and chemical composition of nanoparticles were characterized by high-resolution transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. A mechanism of nanoparticles formation was discussed.

Room Temperature Synthesis of Cu2O Nanospheres: Optical Properties and Thermal Behavior

2014 ◽  
Vol 21 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Daniela Nunes ◽  
Lídia Santos ◽  
Paulo Duarte ◽  
Ana Pimentel ◽  
Joana V. Pinto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Behavior ◽  
Room Temperature ◽  
Diffuse Reflectance Spectroscopy ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

AbstractThe present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.

Synthesis of SrTiO3 Nanoparticles by a Simple Sonochemical Method

2012 ◽  
Vol 424-425 ◽  
pp. 949-952
Author(s):  
Yu Jiang Wang ◽  
Lin Lin Yang ◽  
Yong Gang Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Spherical Shape ◽  
Sonochemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Ultrasonic Time ◽  
Pure Phase

SrTiO3 nanoparticles were successfully synthesized by a sonochemical method at room temperature. The as-prepared powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), and exhibited a pure phase SrTiO3 with a perovskite structure about 20nm in size with uniform and nearly spherical shape. It is found that the size of the obtained nanoparticles increased with prolonging the ultrasonic time.

MICROBE-MEDIATED NANOTRANSFORMATION: CADMIUM

NANO ◽  
2007 ◽  
Vol 02 (04) ◽  
pp. 239-242 ◽  
Author(s):  
ANAL K. JHA ◽  
K. PRASAD ◽  
A. R. KULKARNI
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Individual Nanoparticles

An eco-friendly microbe (lactobacillus sp.)-mediated synthesis of cadmium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Cd nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

PHOTOLUMINESCENCE SPECTRA AND MAGNETIC PROPERTIES OF HYDROTHERMALLY SYNTHESIZED MnO2 NANORODS

2013 ◽  
Vol 27 (29) ◽  
pp. 1350211 ◽  
Author(s):  
ARBAB MOHAMMAD TOUFIQ ◽  
FENGPING WANG ◽  
QURAT-UL-AIN JAVED ◽  
QUANSHUI LI ◽  
YAN LI
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Blue Emission ◽  
Green Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Uv Emission ◽  
Transmission Electron

In this paper, single crystalline tetragonal MnO 2 nanorods have been synthesized by a simple hydrothermal method using MnSO 4⋅ H 2 O and Na 2 S 2 O 8 as precursors. The crystalline phase, morphology, particle sizes and component of the as-prepared nanomaterial were characterized by employing X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). The photoluminescence (PL) emission spectrum of MnO 2 nanorods at room temperature exhibited a strong ultraviolet (UV) emission band at 380 nm, a prominent blue emission peak at 453 nm as well as a weak defect related green emission at 553 nm. Magnetization (M) as a function of applied magnetic field (H) curve showed that MnO 2 nanowires exhibited a superparamagnetic behavior at room temperature which shows the promise of synthesized MnO 2 nanorods for applications in ferrofluids and the contrast agents for magnetic resonance imaging. The magnetization versus temperature curve of the as-obtained MnO 2 nanorods shows that the Néel transition temperature is 94 K.

Au doping effect on the electrical and magnetic properties of Fe3O4 nanoparticles

2015 ◽  
Vol 29 (33) ◽  
pp. 1550213 ◽  
Author(s):  
Asif Mahmood ◽  
Shahid Mahmood Ramay ◽  
Yousef S. Al-Zaghayer ◽  
A. N. AlHazaa ◽  
Waheed A. Al Masary ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Measuring System ◽  
Precipitation Method ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
Transmission Electron ◽  
Auto Combustion

Impurities free ferromagnetic [Formula: see text] was prepared via sol–gel auto-combustion method and then gold was doped with various concentrations 1, 3 and 5 wt.% using conventional deposition–precipitation method. All samples of [Formula: see text] with/without Au doping were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The room temperature magnetic hysteresis loops of all the samples were measured using a physical property measuring system (PPMS), and the results showed a ferromagnetic behavior at room temperature. The results obtained confirmed the fabrication of magnetite–gold composite nanoparticles. The results showed that the resistance and the magnetic behavior of the samples decrease sharply with the increase of Au concentration indicating semiconducting behavior. The saturation magnetization [Formula: see text] of the bare [Formula: see text] sample (94.72 emu/g) is much higher than that (66.78 emu/g) of the 5 wt.% Au-doped [Formula: see text] sample.

SYNTHESIS OF CdTe NANOPARTICLE BY γ-IRRADIATION

2002 ◽  
Vol 01 (05n06) ◽  
pp. 581-585
Author(s):  
SONG JA JO ◽  
YOUNG SOO KANG
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Properties ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Γ Irradiation ◽  
X Ray ◽  
Pl Spectra ◽  
Cdte Nanoparticles ◽  
Transmission Electron

Semiconductor CdTe nanoparticles were synthesized by the γ-irradiation of Cd ion complex at room temperature. Cd-olate complex was reacted with aqueous NaHTe solution. The products were investigated by X-ray Powder Diffraction (XRD) and Transmission Electron Microscopy (TEM). The optical properties of CdTe were investigated with UV-vis and photoluminescence (PL) spectra.

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