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.

scholarly journals Green Synthesis of Co-Zn Spinel Ferrite Nanoparticles: Magnetic and Intrinsic Antimicrobial Properties

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5014
Author(s):  
Alexander Omelyanchik ◽  
Kateryna Levada ◽  
Stanislav Pshenichnikov ◽  
Maryam Abdolrahim ◽  
Miran Baricic ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Chemical Composition ◽  
Saturation Magnetization ◽  
Cobalt Ferrite ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Ferromagnetic Behavior ◽  
Wide Range ◽  
Auto Combustion

Spinel ferrite magnetic nanoparticles have attracted considerable attention because of their high and flexible magnetic properties and biocompatibility. In this work, a set of magnetic nanoparticles of cobalt ferrite doped with zinc was synthesized via the eco-friendly sol-gel auto-combustion method. Obtained particles displayed a room-temperature ferromagnetic behavior with tuned by chemical composition values of saturation magnetization and coercivity. The maximal values of saturation magnetization ~74 Am2/kg were found in cobalt ferrite nanoparticles with a 15–35% molar fraction of cobalt replaced by zinc ions. At the same time, the coercivity exhibited a gradually diminishing trend from ~140 to ~5 mT whereas the concentration of zinc was increased from 0 to 100%. Consequently, nanoparticles produced by the proposed method possess highly adjustable magnetic properties to satisfy the requirement of a wide range of possible applications. Further prepared nanoparticles were tested with bacterial culture to display the influence of chemical composition and magnetic structure on nanoparticles-bacterial cell interaction.

The origin of ferromagnetism of Co-doped TiO2 nanoparticles: Experiments and theory investigation

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650296 ◽  
Author(s):  
Suyin Zhang ◽  
Zhongpo Zhou ◽  
Rui Xiong ◽  
Jing Shi ◽  
Zhihong Lu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
First Principles ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
First Principles Calculation ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
3D Electron ◽  
Co Doped

A series of Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ([Formula: see text] = 0.01, 0.03, 0.05, 0.07) nanoparticles were synthesized by sol–gel method. The X-ray diffraction, transmission electron microscopy, Raman analysis and X-ray photoelectron spectroscopy ruled out the signatures of Ti[Formula: see text], Co-clusters or any other oxides of Co. The ferromagnetic behavior was clearly observed at room temperature in doped samples with saturation magnetization [Formula: see text] of the order of 0.008–0.035 emu/g depending on doping concentrations. The saturation magnetization is found to be increased with the Co contents increasing from 1% to 7%. From the plot of the M–T curve, we obtain the [Formula: see text] as [Formula: see text][Formula: see text]515 K for 5% Co-doped TiO2. Oxygen vacancies were detected from the photoluminescence (PL) measurement. Magnetic properties analyses and PL analyses showed that oxygen vacancies probably played a major role in ferromagnetism of the Ti[Formula: see text]Co[Formula: see text]O2 system with Co substituting for Ti. The first-principles calculation was performed to investigate the magnetic properties of Co-doped TiO2 nanoparticles. It can be found that the major magnetic moment is from the 3d electron of Co. The experiment results are consistent with the first-principles calculation. The ferromagnetism derived from the spin-split of O-2p and Co-3d electron states caused by p–d orbit hybridization.

scholarly journals Effect of bismuth substitution on magnetic properties of CoFe2O3 nanoparticles: Study of synthesize using coprecipitation method

2019 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Didik Eko Saputro ◽  
Utari Utari ◽  
Budi Purnama
Keyword(s):  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Saturation Magnetization ◽  
Coercive Field ◽  
Cobalt Ferrite ◽  
Ferrite Nanoparticles ◽  
Coprecipitation Method ◽  
Ion Concentration ◽  
Cobalt Ferrite Nanoparticles ◽  
Ion Substitution

<strong><span lang="EN-US">Abstract:</span></strong><span lang="EN-US"> The effect of bismuth ion substitution on the magnetic properties of cobalt ferrite nanoparticles was identified in this study. This method used in this study was coprecipitation method using 0.1 bismuth ion concentration. The results on hysteresis loop showed that the saturation magnetization of cobalt ferrite nanoparticles decreased with the substitution of bismuth ions, but the coercive field experienced the opposite. Saturation magnetization decreased from 57.97 to 51.19 emu / g, while coercive fields increased from 0.64 to 0.84 kOe.</span>

STRUCTURE AND MAGNETIC PROPERTIES OF NONOSIZED SnO-Fe2O3 MATERIAL OBTAINED BY BALL MILLING

2010 ◽  
Vol 09 (06) ◽  
pp. 567-570
Author(s):  
AHMED M. AL-SAIE ◽  
ADNAN JAAFAR ◽  
MOHAMED BOUOUDINA
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Diffraction Pattern ◽  
Ball Milling ◽  
Magnetic Measurements ◽  
Spinel Phase ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Peaks

A mixture of Fe 2 O 3 and SnO oxides has been mechanically milled to form SnFe 2 O 4 spinel phase. X-ray diffraction pattern of the milled mixture shows that after milling, both peaks of Fe 2 O 3 and SnO remain with a drastic decrease of their intensities and broadening. The appearance of a broad halo around 2θ ~ 31° indicates the formation of an amorphous phase. After annealing at 750°C for 1 h, SnO peaks disappear completely and new diffraction peaks emerge indicating the formation of a new nanophase i.e. SnO 2. Magnetic measurements of the as-milled mixture show a ferromagnetic behavior with saturation magnetization Ms = 6.8 emu/g which drastically decreases after annealing to 0.6 emu/g.

A nickel(ii)–manganese(ii)-azido layered coordination polymer showing a three-dimensional ferrimagnetic order at 35 K

2018 ◽  
Vol 47 (3) ◽  
pp. 836-844 ◽  
Author(s):  
Sagar Ghosh ◽  
Shuvayan Roy ◽  
Cai-Ming Liu ◽  
Sasankasekhar Mohanta
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Coordination Polymer ◽  
Hysteresis Loop ◽  
Long Range ◽  
Three Dimensional ◽  
Molecular Magnet ◽  
Two Dimensional ◽  
Ferrimagnetic Ordering

The synthesis, crystal structure and magnetic properties of a two-dimensional nickel(ii)–manganese(ii)–azido system are described. It is an interesting molecular magnet because it exhibits long-range ferrimagnetic ordering at a Tc of 35 K and a hysteresis loop up to 20 K.

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.

Structural, Morphological and Magnetic Characterization of Sm-substituted Ni-Zn Ferrite

2020 ◽  
Vol 10 (2) ◽  
pp. 152-156 ◽  
Author(s):  
Muhammad Hanif bin Zahari ◽  
Beh Hoe Guan ◽  
Lee Kean Chuan ◽  
Afiq Azri bin Zainudin
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Saturation Magnetization ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Rare Earth Ions ◽  
Ion Concentration ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Combustion Technique

Background: Rare earth materials are known for its salient electrical insulation properties with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4 (x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated. Methods: A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural, morphological and magnetic properties of the samples were examined through X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer (VSM) measurements. Results: XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+ concentration increases. Conclusion: The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization can be explained based on weak super exchange interaction between A and B sites. The difference in magnetic properties between the samples despite the slight difference in Sm3+ concentrations suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need, through the substitution of Fe3+ with rare earth ions.

The Structure and Magnetic Properties of NiZn-Ferrite Films Deposited by Magnetron Sputtering at Room Temperature

2013 ◽  
Vol 690-693 ◽  
pp. 1702-1706 ◽  
Author(s):  
Shuang Jun Nie ◽  
Hao Geng ◽  
Jun Bao Wang ◽  
Lai Sen Wang ◽  
Zhen Wei Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetron Sputtering ◽  
Saturation Magnetization ◽  
Room Temperature ◽  
Oxygen Flow ◽  
Flow Ratio ◽  
Study Results ◽  
Ferrite Thin Films ◽  
Ferrite Films

NiZn-ferrite thin films were deposited onto silicon and glass substrates by radio frequency magnetron sputtering at room temperature. The effects of the relative oxygen flow ratio on the structure and magnetic properties of the thin films were investigated. The study results reveal that the films deposited under higher relative oxygen flow ratio show a better crystallinity. Static magnetic measurement results indicated that the saturation magnetization of the films was greatly affected by the crystallinity, grain dimension, and cation distribution in the NiZn-ferrite films. The NiZn-ferrite thin films with a maximum saturation magnetization of 151 emucm-3, which is about 40% of the bulk NiZn ferrite, was obtained under relative oxygen flow ratio of 60%.

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

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