Clarification of the ordering of intercalated Fe atoms in Fe x TiS2 and its effect on the magnetic properties

2021 ◽  
Vol 77 (3) ◽  
Author(s):  
Yi Ling Chiew ◽  
Masanobu Miyata ◽  
Mikio Koyano ◽  
Yoshifumi Oshima
Keyword(s):  
Magnetic Properties ◽  
Quantum Interference ◽  
Magnetic Measurements ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Local Strain ◽  
Partial Ordering ◽  
Chemical Vapor Transport ◽  
Ferromagnetic Behavior ◽  
Spin Glass Behavior

Even though there has been a lot of studies on the magnetic properties of Fe x TiS2 and their corresponding atomic structures at different Fe concentrations, the dependency of the properties on the Fe atomic arrangement has not been fully clarified yet. In this study, Fe x TiS2 structures, synthesized by chemical vapor transport technique at Fe concentrations of 0.05, 0.10, 0.15, 0.20 0.25 and 0.33, were observed three-dimensionally using a transmission electron microscope and their corresponding magnetization values were measured using a superconducting quantum interference device. The results show a switch from local in-plane two-dimensional (2D) ordering of \sqrt 3 a and 2a at concentrations below 0.15 to three-dimensional (3D) ordering of 2a × 2a × 2c at x = 0.20 and 0.25, as well as \sqrt 3 a × \sqrt 3 a × 2c superstructures at x = 0.33, although it should be noted that the x = 0.20 sample only had partial ordering of Fe atoms. The type of Fe ordering present in Fe x TiS2 could be explained by the balance of cohesive energy of neighboring Fe atoms and local strain energy imposed on the host structure due to the formation of Fe clusters. It is also found that the switch from 2D to 3D Fe order coincides with the magnetic measurements, which reveal spin-glass behavior below x = 0.15 and ferromagnetic behavior above x = 0.20. This suggests that the magnetic properties of the Fe x TiS2 structure are highly influenced by the ordering of Fe atoms between planes.

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.

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.

scholarly journals Influence of Boron Content on the Solidification Structure, Magnetic Properties and Hot Mechanical Behavior in an Advanced As-Cast TWIP Steel

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1230
Author(s):  
A. E. Salas-Reyes ◽  
G. Altamirano-Guerrero ◽  
J. F. Chávez-Alcalá ◽  
A. Barba-Pingarrón ◽  
I. A. Figueroa ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Boron Content ◽  
Twip Steel ◽  
Magnetic Measurements ◽  
Research Work ◽  
Constant Strain Rate ◽  
Solidification Structure ◽  
Ferromagnetic Behavior ◽  
Hot Ductility ◽  
Low Carbon

This research work reports the effect of boron micro-additions (180 and 470 ppm) on the solidification structure, magnetic properties and hot ductility behavior of an advanced low-carbon highly alloyed twinning-induced plasticity (TWIP) steel. For this purpose, three experimental TWIP steels were fabricated by melting commercial raw materials and casting into metallic molds. Solidification structure was characterized by means of optical and scanning electron microscopy techniques, and a statistical study was carried out to measure dendrite features. A vibrating sample magnetometer was used, at room temperature, to determine magnetic properties, and a X-ray diffraction analysis was performed in order to identify the related phases during magnetic measurements. Finally, the hot ductility in the as-cast condition was evaluated at 700, 900 and 1100 °C, under a constant strain rate of 0.001 s−1. The results indicate that boron micro-additions cause an overall refining solidification structure and austenitic grain size. However, as the boron content increases, segregation of this element promotes formation of ferrite and ε-martensite, leading to ferromagnetic behavior. Nonetheless, with subsequent hot- and cold-rolling, the single austenitic phase is achieved, and this behavior is eliminated. Hot tensile tests revealed that boron micro-addition is beneficial to the hot ductility behavior. The greatest influence was observed for the higher concentration of boron (470 ppm). In comparison with the steel without boron content, the reduction of area (RA) is more than the triple of the hot workability during straining at 900 °C. Thus, present results demonstrate that boron micro-addition has an excellent potential for refining dendritic microstructure and improving the hot-deformation behavior of present low-carbon highly alloyed TWIP steel.

scholarly journals Fabrication of Micron Scale Magnetic Nickel Features by Selective Area Organometallic Chemical Vapor Deposition

1997 ◽  
Vol 475 ◽  
Author(s):  
D. Welipitiya ◽  
C. N. Borca ◽  
P. A. Dowben ◽  
I. Gobulukoglu ◽  
Hong Jiang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Magnetic Measurements ◽  
Chemical Vapor ◽  
Gradient Force ◽  
Selective Area ◽  
Wide Range ◽  
Radiation Induced ◽  
Organometallic Chemical Vapor Deposition

AbstractWe demonstrate that it is possible to deposit a wide range of magnetic features, using photoassisted and electron radiation induced selective area organometallic chemical vapor deposition. Large arrays of identical micron to nano scale Ni features were deposited by these methods. Their magnetic properties were studied by alternating gradient force magnetometry as well as magnetic force microscopy. Our morphological and magnetic measurements show that the structures are spatially well defined, and the magnetic properties are related to the structural shapes of the features.

scholarly journals Optical and Magnetic Properties of Fe Doped ZnO Nanoparticles Obtained by Hydrothermal Synthesis

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xiaojuan Wu ◽  
Zhiqiang Wei ◽  
Lingling Zhang ◽  
Xuan Wang ◽  
Hua Yang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Measurements ◽  
Magnetic Semiconductors ◽  
Energy Dispersive Spectrometer ◽  
Blue Shift ◽  
Ferromagnetic Behavior ◽  
Optical And Magnetic Properties ◽  
Doped Zno

Diluted magnetic semiconductorsZn1-xFexOnanoparticles with different doping concentration (x=0, 0.01, 0.05, 0.10, and 0.20) were successfully synthesized by hydrothermal method. The crystal structure, morphology, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), Raman scattering spectra (Raman), photoluminescence spectra (PL), and the vibrating sample magnetometer (VSM). The experiment results show that all samples synthesized by this method possess hexagonal wurtzite crystal structure with good crystallization, no other impurity phases are observed, and the morphology of the sample shows the presence of ellipsoidal nanoparticles. All theFe3+successfully substituted for the lattice site ofZn2+and generates single-phaseZn1-xFexO. Raman spectra shows that the peak shifts to higher frequency. PL spectra exhibit a slight blue shift and the UV emission is annihilated with the increase ofFe3+concentration. Magnetic measurements indicated that Fe-doped ZnO samples exhibit ferromagnetic behavior at room temperature and the saturation magnetization is enhanced with the increase of iron doping content.

Magnetic Properties and Scaling Behavior in Perovskite–like La0.7(Ba1−xPbx)0.3CoO3 System

2001 ◽  
Vol 674 ◽  
Author(s):  
Chiung-Hsiung Chen ◽  
Ting-Sheng Huang ◽  
Ming-Fong Tai
Keyword(s):  
Magnetic Properties ◽  
Magnetic Measurements ◽  
Mean Field Theory ◽  
Mean Field ◽  
Three Dimensional ◽  
Scaling Behavior ◽  
Magnetic Data ◽  
Crystallographic Structure ◽  
Ferromagnetic Transition ◽  
Diffraction Patterns

ABSTRACTIn this study, we used x-ray diffraction patterns and dc magnetic measurements to investigate the crystallographic structure, magnetic properties and scaling behavior of the distorted perovskite La0.7(Ba1−xPbx)0.3CoO3 (0 ≤ x ≤ 0.5) system with a constant ratio of Co4+/Co3+. Samples with x = 0.0 and 0.1 were crystallized in the cubic structure with a ∼ 7.76 Å whereas samples with x ≥ 0.2 were crystallized in an orthorhombic Pbnm space group with a ∼ b ∼ 5.50 Å and c ∼ 7.85 Å. For all our samples the spin-glass-like behavior were observed in low temperature and low field ranges. The Pb2+ substitution on Ba2+ site does not significantly affect the ferromagnetic transition temperature TC, but does introduce large variation in the magnetic strength. In both the ferromagnetic and paramagnetic states the minimum values of the average effective moments provided by every Co ion occur at x = 0.3. We also observed the scaling behaviors of magnetic data in all samples. The derived values of the critical exponents (β, γ, δ) were consistent with those predicted by mean field theory and a three-dimensional Heisenberg model.

Room Temperature Ferromagnetic Properties of Epitaxially Grown Zn1-xCoxO Thin Films

2004 ◽  
Vol 834 ◽  
Author(s):  
F. Yun ◽  
Varatharajan Rengarajan ◽  
J. Nause ◽  
H. Morkoç
Keyword(s):  
Thin Films ◽  
Quantum Interference ◽  
Gas Flow ◽  
Magnetic Hysteresis ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Ferromagnetic Behavior ◽  
Zero Field ◽  
Metal Organic ◽  
Carrier Gas Flow

ABSTRACTWe have conducted a systematic magnetic characterization of a series of Zn1-xCoxO samples with different cobalt composition. The Zn1-xCoxO thin films were epitaxially grown by metal organic chemical vapor deposition (MOCVD) on quartz and ZnO substrates. The Co composition was adjusted by controlling the bubbler temperature and carrier gas flow. The magnetization measurements were performed using a Quantum Design MPMS system, which utilizes a superconducting quantum interference device (SQUID) magnetometer. Magnetic hysteresis curves were observed at 5K which persisted up to 300K, possibly characteristic of ferromagnetic behavior. Temperature dependent magnetization was recorded under both zero-field cooled (ZFC) and field cooled (FC) conditions. Changes of magnetization were observed under ZFC and FC conditions in some samples from 5K up to 300K. Composition-dependent changes in magnetization were also observed among samples with different cobalt doping, indicative of ferromagnetism related directly to cobalt incorporation. Magnetic field dependent magnetization at various temperatures with field up to 5 Tesla suggests the Zn1-xCoxO layers were not paramagnetic.

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.

Magnetic Properties of Mn-Doped ZnO Nanostructures Synthesized by Chemical Vapor Transport

2006 ◽  
Vol 45 (10A) ◽  
pp. 7688-7690 ◽  
Author(s):  
Hua-Wei Zhang ◽  
Er-Wei Shi ◽  
Zhi-Zhan Chen ◽  
Xue-Chao Liu ◽  
Bing Xiao
Keyword(s):  
Magnetic Properties ◽  
Chemical Vapor ◽  
Vapor Transport ◽  
Chemical Vapor Transport ◽  
Zno Nanostructures ◽  
Doped Zno ◽  
Mn Doped

Growth and Magnetic Properties of Three-Dimensional Firtree-Like Cobalt Microcrystals with Hierarchical Dendritic Superstructures

2015 ◽  
Vol 645-646 ◽  
pp. 104-109 ◽  
Author(s):  
Xi Yang ◽  
Zhi Bing Fu ◽  
Lei Yuan ◽  
Chao Yang Wang ◽  
Qian Wang Chen
Keyword(s):  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Saturation Magnetization ◽  
Three Dimensional ◽  
Main Axis ◽  
Ferromagnetic Behavior ◽  
Layer By Layer ◽  
Hexagonal Arrangement ◽  
Pyridine Carboxylate

Novel ordered three-dimensional (3D) firtree-like hexagonal cobalt microcrystals with hierarchical dendritic superstructures have been obtained by using cobalt bis (4-pyridine carboxylate) tetrahydrate as the precursor of Co. The 3D dendrite has a main axis and the leaves arrange layer by layer in parallel along the axis, which exhibit the radiate hexagonal arrangement from the axis in a layer. The main axis of the dendrite grows along the [001] direction of hexagonal Co and the leaves grow parallel to the (001) plane. The hysteresis loop of the sample shows a ferromagnetic behavior with the saturation magnetization of 134.0 emu/g and the coercivity of 184.9 Oe. It is noted that the coercivity is relatively low compared with that of the cobalt dendritic crystallites reported previously, which may result from the lower total morphology anisotropy of our sample.

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