scholarly journals Room Temperature Ferromagnetic and Optical Properties of Chrome Doped ZnS Nanorods Prepared by Hydrothermal Method

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Wenhua Zhao ◽  
Zhiqiang Wei ◽  
Li Zhang ◽  
Xiaojuan Wu ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Room Temperature ◽  
Single Phase ◽  
Diffuse Reflectance Spectroscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
Pl Spectra ◽  
Cr Concentration

Cr doped Zn1-xCrxS nanorods with different concentration ratio (x=0, 0.01, 0.03, and 0.05) were successfully synthesized by hydrothermal method. The crystal microstructure, morphology, chemical composition, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra, and the vibrating sample magnetometer (VSM). All the samples synthesized by this method exhibited single-phase wurtzite structure with good crystallization as demonstrated by XRD studies, which indicated that all Cr ions successfully substituted for the lattice site of Zn2+ and generated single-phase Zn1-xCrxS. DRS revealed the band gap of doped Zn1-xCrxS underwent blue shift compared to that of the bulk ZnS. PL spectra showed obvious ultraviolet emission peak at 375 nm and two blue emissions appear about 500 and 580 nm. The blue emissions intensity of doped samples improved with the increase of Cr concentration, comparing to pure ZnS. Magnetic measurements indicated that the undoped and doped ZnS nanorods exhibited well-defined ferromagnetic behavior at room temperature. The saturation magnetization weakened significantly with increasing Cr concentration comparing to pure ZnS and reached minimum for 3% Cr.

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.

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.

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.

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 Self-Assembly of TiO2/CdS Mesoporous Microspheres with Enhanced Photocatalytic Activity via Hydrothermal Method

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sujing Yu ◽  
Juncheng Hu ◽  
Jinlin Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Activity ◽  
Hydrothermal Method ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray ◽  
Transmission Electron ◽  
Mesoporous Microspheres

Self assembly of TiO2/CdS mesoporous microspheres was synthesized via hydrothermal method. The samples were characterized by X-ray powder diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), energy-dispersive spectroscopy analysis (EDS), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra (PL). The as-synthesized TiO2/CdS mesoporous microspheres showed superior photocatalytic activity for the degradation of RhB under either visible light or simulated sunlight irradiation; the 10 wt% TiO2/CdS sample showed the best performance. Moreover, this catalyst showed improved stability, and the activity did not decrease significantly after four recycles. The heterojunction between TiO2and CdS may be favorable for the transport of photoinduced electrons from CdS to TiO2. In addition, the mesoporous structure could increase the utilization of light energy and facilitate the diffusion of reactants and products during the photocatalytic reaction.

Physical and Dielectric Properties of MnFe2O4 Doped by Mo

2019 ◽  
Vol 4 (2) ◽  
pp. 125-136 ◽  
Author(s):  
F. Al-Mokdad ◽  
R. Sayed Hassan ◽  
R. Awad
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Energy Gap ◽  
Magnetic Measurements ◽  
Magnetic Hysteresis ◽  
Spinel Ferrites ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
Mo Doping ◽  
Mnfe2o4 Nanoparticles

Background: The properties of spinel ferrites are known to be dependent on many various factors and mainly on the cations distribution among the tetrahedral and octahedral sites. Therefore, they are sensitive to the presence of doping cations, the type and the amount of these cations. Many researchers have focused on investigating the effect of doping on spinel ferrites nanoparticles with various types of dopants. Among the dopants, transition metal (TM) ions have shown significant effects and changes on the structural, optical, electric and magnetic properties of spinel ferrites nanoparticles. Objective: The goal of this work is to investigate the effect of the TM ions Mo5+ on the several properties of manganese ferrites nanoparticles. Methods: Mo-doped manganese ferrites nanoparticles with the general formula MnFe2-xMoxO4 (0≤x≤ 0.1) were prepared by co-precipitation technique using two different methods, depending on the molarity of NaOH and the annealing temperatures. The characterization of the prepared samples was conducted by X-ray powder diffraction (XRD), Energy-Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), ultraviolet-visible (UV-Vis) absorption spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy in order to investigate the effect of Mo-doping on the structure, crystallite size, morphology, energy gap and functional groups of MnFe2O4 nanoparticles. Vibrating sample magnetometer (VSM) was used to study the magnetic hysteresis of the samples. Results: The XRD patterns show the segregation of MnFe2O4 phase into α-Fe2O3 and Mn2O3 for samples prepared at 4 M NaOH and annealing temperature of 873 K. Whereas, samples prepared at 2 M NaOH without annealing process, obtained a single phase of MnFe2O4. The Eg of both samples decreases with the increase in Mo-doping. FTIR confirms the presence of Fe-O bands corresponding to α-Fe2O3 for annealed samples, and the metal-O bands corresponding to octahedral and tetrahedral sites in non-annealed samples. Magnetic measurements show that annealed samples are antiferromagnetic whereas ferromagnetic behavior is observed in non-annealed samples. Dielectric measurements, for both samples, indicate that the dielectric parameters are strongly dependent on both Mo-concentrations and temperatures. Conclusion: In order to get a single phase of MnFe2O4 nanoparticles, thermal treatment at high temperature and high molarity of NaOH are not recommended. Mo-doping has significant influences on the optical, magnetic and dielectric properties and therefore future studies on the Mo-doping with different and new doping percentages are recommended.

scholarly journals Magnetic Binary Supersaturated Solid Solutions Processed by Severe Plastic Deformation

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 6 ◽  
Author(s):  
Martin Stückler ◽  
Heinz Krenn ◽  
Reinhard Pippan ◽  
Lukas Weissitsch ◽  
Stefan Wurster ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Pressure Torsion ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
Dual Phase ◽  
X Ray Diffraction ◽  
Magnetic Phases ◽  
X Ray ◽  
Supersaturated Solid Solutions

Samples consisting of one ferromagnetic and one diamagnetic component which are immiscible at the thermodynamic equilibrium (Co-Cu, Fe-Cu, Fe-Ag) are processed by high-pressure torsion at various compositions. The received microstructures are investigated by electron microscopy and synchrotron X-ray diffraction, showing a microstructural saturation. Results gained from microstructural investigations are correlated to magnetometry data. The Co-Cu samples show mainly ferromagnetic behavior and a decrease in coercivity with increasing Co-content. The saturation microstructure of Fe-Cu samples is found to be dual phase. Results of magnetic measurements also revealed the occurrence of two different magnetic phases in this system. For Fe-Ag, the microstructural and magnetic results indicate that no intermixing between the elemental phases takes place.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

2020 ◽  
Vol 16 (4) ◽  
pp. 655-666
Author(s):  
Mona Rekaby
Keyword(s):  
Magnetic Properties ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Structural Defects ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Antiferromagnetic Ordering ◽  
Doped Zno ◽  
Co Doped

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

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