scholarly journals Influence of Fe-Doping on the Structural and Magnetic Properties of ZnO Nanopowders, Produced by the Method of Pulsed Electron Beam Evaporation

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
V. G. Il’ves ◽  
S. Yu. Sokovnin ◽  
A. M. Murzakaev
Keyword(s):  
Magnetic Properties ◽  
Electron Beam ◽  
Magnetic Measurements ◽  
Electron Beam Evaporation ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Defective Structure ◽  
Pulsed Electron Beam ◽  
Scanning Transmission ◽  
Structural And Magnetic Properties

The nanopowders (NPs) ZnO-Zn-Fe and ZnO-Fe with the various concentrations of Fe (xFe) (0≤xFe≤0.619mass.%) were prepared by the pulsed electron beam evaporation method. The influence of doping Fe on structural and magnetic properties of NPs was investigated. X-ray diffraction showed that powders contain fine-crystalline and coarse-crystalline ZnO fractions with wurtzite structure and an amorphous component. Secondary phases were not found. The magnetic measurements made at room temperature, using the vibration magnetometer and Faraday’s scales, showed ferromagnetic behavior for all powders. Magnetization growth of NPs ZnO-Zn and ZnO-Zn-Fe was detected after their short-term annealing on air at temperatures of 300–500°C. The growth of magnetization is connected with the increase in the concentration of the phase ZnO with a defective structure as the result of oxidation nanoparticles (NPles) of Zn. The scanning transmission electron microscopy (STEM) showed a lack of Fe clusters and uniform distribution of atoms dopant in the initial powder ZnO-Zn-Fe. A lack of logical correlation between magnetization and concentration of a magnetic dopant of Fe in powders is shown.

Structural and magnetic properties of pure and cobalt doped Gallium Nitride nanocrystals

2010 ◽  
Vol 1257 ◽  
Author(s):  
Vottikondala Ganesh ◽  
Suresh Sundaram ◽  
Krishnan Baskar
Keyword(s):  
Magnetic Properties ◽  
Gallium Nitride ◽  
Magnetic Measurements ◽  
Raw Materials ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
Co Doped

AbstractIn the present study pure and doped gallium nitride (GaN) nanocrystals were synthesized using gallium trichloride (GaCl3), ethylene diamine tetra acetic acid (EDTA) and cobalt chloride as raw materials at a temperature of 900 °C in ammonia (NH3) atmosphere. The XRD spectrum for pure and cobalt doped GaN nanocrystals shows the formation of single phase wurtzite structure. No impurity phases were observed in the X-ray diffraction pattern for 5% Co doped sample whereas secondary phases were observed when the doping concentration exceeds 5 %. Shift in X-ray diffraction peaks were observed in Co doped samples towards lower angle side compared to pure GaN, it confirms that the Co atoms introduces in to the GaN lattice. Transmission electron microscopy images were taken for pure and Co doped GaN. Hexagonal morphology was observed in pure GaN samples. The average size of the particle was found to be ˜20 nm for pure and Co doped GaN. The magnetic measurements were carried out for the Co (5% & 10%) doped samples both at 10K and 300K. Clear hysteresis loop in the magnetization curve suggest the presence of ferromagnetic behavior in cobalt doped GaN. Temperature dependent magnetization (M-T) measurements were also carried out for doped samples using Super Conducting Quantum Interface Device (SQUID) from 10K to 300K The results have been discussed and correlated to structural and magnetic properties of the materials.

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.

Structural and magnetic properties of SmCo-based magnetic films grown by electron-beam evaporation

2015 ◽  
Vol 385 ◽  
pp. 313-317 ◽  
Author(s):  
P. Saravanan ◽  
V.T.P. Vinod ◽  
Miroslav Černík ◽  
R. Vishnuraj ◽  
J. Arout Chelvane ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electron Beam ◽  
Magnetic Films ◽  
Electron Beam Evaporation ◽  
Structural And Magnetic Properties

Structural and Magnetic properties of Cr-diffused CdTe nanocrystalline thin films deposited by electron beam evaporation

2014 ◽  
Vol 117 (2) ◽  
pp. 793-798 ◽  
Author(s):  
M. Rigana Begam ◽  
N. Madhusudhana Rao ◽  
S. Kaleemulla ◽  
C. Krishnamoorthi ◽  
N. Sai Krishna ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Electron Beam ◽  
Electron Beam Evaporation ◽  
Structural And Magnetic Properties ◽  
Nanocrystalline Thin Films

Structural and Magnetic Properties of Co diffused CdTe Nanocrystalline Thin Films Deposited by Electron Beam Evaporation

2014 ◽  
Vol 27 (9) ◽  
pp. 2147-2152 ◽  
Author(s):  
Rigana Begam Mohamed ◽  
Madhusudhana Rao Nasina ◽  
Kaleemulla Shaik ◽  
Sai Krishna Narayananellore ◽  
Kuppan M
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Electron Beam ◽  
Electron Beam Evaporation ◽  
Structural And Magnetic Properties ◽  
Nanocrystalline Thin Films

Structural and Magnetic Properties of Cr- and Fe-Doped CeO2 Nanoparticles Prepared by Sol-Gel Method

2016 ◽  
Vol 848 ◽  
pp. 682-687 ◽  
Author(s):  
Sheng Hong Yang ◽  
Yue Li Zhang
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Measurements ◽  
Physical Property Measurement System ◽  
Sol Gel ◽  
Physical Property ◽  
Ferromagnetic Behavior ◽  
Sem Images ◽  
Uniform Size ◽  
Structural And Magnetic Properties

A study of the structural and magnetic properties of Cr-and Fe-doped CeO2 nanoparticles produced by the sol–gel-based method was undertaken. The crystal structure and phase, morphology, and magnetic properties of the sample were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (Raman) and physical property measurement system (PPMS). XRD and Raman studied showed that Cr-and Fe-doped did not change CeO2 original cubic fluorite crystal structure, and no ferromagnetic secondary phase was observed. SEM images showed that Cr-and Fe-doped CeO2 nanoparticles were spherical, uniform size, and good dispersion. The particle size was about 20 nm. The magnetic measurements showed that the Cr-and Fe-doped CeO2 nanoparticles presented ferromagnetic behavior at 10 and 300 K, indicating the Curie temperature was above room temperature. The magnetization diminished with the increase of the temperature. The saturation magnetization and coercivity of Fe-doped CeO2 nanoparticles were higher than that of Cr-doped CeO2 nanoparticles. Combined with the results of XRD and Raman, the ferromagnetic behavior can be attributed to the intrinsic properties of Cr-and Fe-doped CeO2 nanostructures.

Synthesis and Structural Characterization of Ferromagnetic Au/Co Nanoparticles

2014 ◽  
Vol 1708 ◽  
Author(s):  
Nabraj Bhattarai ◽  
Subarna Khanal ◽  
Daniel Bahena ◽  
Robert L. Whetten ◽  
Miguel Jose-Yacaman
Keyword(s):  
Quantum Interference ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
Contrast Imaging ◽  
Uniform Size ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Co Nanoparticles ◽  
Z Contrast

ABSTRACTThe synthesis of bimetallic magnetic nanoparticles is very challenging because of the agglomeration and non-uniform size. In this paper, we present the synthesis of monodispersed 3-5 nm sized thiolated bimetallic alloyed Au/Co nanoparticles with decahedral and icosahedral shape, their characterization using Cs-corrected scanning transmission electron microscopy (STEM) and magnetic measurements using superconducting quantum interference device (SQUID) magnetometer. The Z-contrast imaging and energy dispersive X-ray spectroscopy (EDS) mapping showed an inhomogeneous alloying with minor segregation between Au and Co at nanoscale and the SQUID measurement exhibited the ferromagnetic behavior.

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