scholarly journals Electrospun Fe3O4-PVDF Nanofiber Composite Mats for Cryogenic Magnetic Sensor Applications

Textiles ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 227-238
Author(s):  
Tonoy Chowdhury ◽  
Nandika D’Souza ◽  
Diana Berman
Keyword(s):  
Polyvinylidene Fluoride ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Mechanical Stability ◽  
Composite Fiber ◽  
Piezoelectric Response ◽  
Piezoelectric Composite ◽  
Ferromagnetic Behavior ◽  
Fiber Mats ◽  
Ft Ir

Magnetically responsive, mechanically stable and highly flexible iron (III) oxide-polyvinylidene fluoride (Fe3O4-PVDF) piezoelectric composite fiber mats were fabricated via one step electrospinning method for magnetic sensing at cryogenic temperature. The properties of Fe3O4-PVDF composite fiber mats were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, d33 and magnetization test. The fiber diameter decreased as the concentration of Fe3O4 increased. The DSC results suggested a decrease in the crystallinity of the composite fiber mats after adding Fe3O4, and the XRD curves identified that the decrease in crystallinity took place in the β crystalline phases of the fibers. FT-IR results further confirmed the reduction of β phases of the composite fiber mats which dropped the piezoelectric response of the fiber mats by 38% for 5% Fe3O4-PVDF than PVDF fiber but still 400% higher than PVDF pellets. The magnetization test advocated a superparamagnetic state of the fiber at room temperature but a ferromagnetic behavior at a lower temperature. The coercivity values of the mats suggested a homogeneous dispersion of the Fe3O4 nanoparticles into the PVDF matrix. Young’s modulus (E) of the fibers remained the same before and after the magnetization test, indicating the mechanical stability of the fiber in the range of 5 K to 300 K. Its mechanical stability, superparamagnetic behavior at room temperature and ferromagnetic at low temperature could open up its application in spintronic devices at cryogenic temperature and cryogenic power electronic devices.

Enhanced magnetoelectric coupling and dielectric constant in flexible ternary composite electrospun fibers of PVDF-HFP loaded with nanoclay and NiFe2O4 nanoparticles

2020 ◽  
Vol 44 (26) ◽  
pp. 11356-11364
Author(s):  
Sobi K. Chacko ◽  
M. T. Rahul ◽  
B. Raneesh ◽  
Nandakumar Kalarikkal
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Composite Fiber ◽  
Magnetoelectric Coupling ◽  
Electrospun Fibers ◽  
Fiber Mats ◽  
Ternary Composite ◽  
Magnetoelectric Properties ◽  
Nife2o4 Nanoparticles

Magnetoelectric flexible composite fiber mats with superior room temperature magnetoelectric properties.

Structural and Magnetic Properties of Cobalt and Aluminum Co-Doped ZnO Powders

2008 ◽  
Vol 47-50 ◽  
pp. 600-603
Author(s):  
Yan Yan Wei ◽  
Deng Lu Hou ◽  
Rui Bin Zhao ◽  
Zhen Zhen Zhou ◽  
Cong Mian Zhen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Ferromagnetic Behavior ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Al Content ◽  
Infrared Reflection ◽  
Zno Powders ◽  
Ft Ir

A series of Zn0.95-xCo0.05AlxO (x=0, 0.01, 0.02, 0.05, 0.08, 0.10) powders with different percentages of aluminum was fabricated using the sol-gel method. X-ray diffraction (XRD) revealed that the Co ions and Al ions substitute for Zn2+ ions without changing the wurtzite structure. No impurity phases were found. No clusters or precipitates of cobalt or aluminum were found using scanning electron microscope analysis. Fourier transform-infrared reflection (FT-IR) spectrometry was used to examine the infrared transmission properties and revealed that Co ions were incorporated into the lattice as Co2+ substituting for Zn2+. Ferromagnetic behavior in the samples was obtained at room temperature. As the Al content x increased, the room temperature ferromagnetism of the samples was reduced, and when x increased to 0.08, the room temperature ferromagnetism disappeared.

scholarly journals Piezoelectric Properties of PVDF-Zn2GeO4 Fine Fiber Mats

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5936
Author(s):  
Fariha Rubaiya ◽  
Swati Mohan ◽  
Bhupendra B. Srivastava ◽  
Horacio Vasquez ◽  
Karen Lozano
Keyword(s):  
Polyvinylidene Fluoride ◽  
Composite System ◽  
Fiber Composite ◽  
Beta Phase ◽  
Piezoelectric Response ◽  
X Ray Diffraction ◽  
Fiber Mats ◽  
Portable Electronics ◽  
Fine Fiber ◽  
Potential Applications

The current paper presents the development and characterization of polyvinylidene fluoride (PVDF)-Zn2GeO4 (ZGO) fine fiber mats. ZGO nanorods (NRs) were synthesized using a hydrothermal method and incorporated in a PVDF solution to produce fine fiber mats. The fiber mats were prepared by varying the concentration of ZGO NRs (1.25–10 wt %) using the Forcespinning® method. The developed mats showed long, continuous, and homogeneous fibers, with average fiber diameters varying from 0.7 to 1 µm, depending on the ZGO concentration. X-ray diffraction spectra depicted a positive correlation among concentration of ZGO NRs and strengthening of the beta phase within the PVDF fibers. The composite system containing 1.25 wt % of ZGO displayed the highest piezoelectric response of 172 V. This fine fiber composite system has promising potential applications for energy harvesting and the powering of wearable and portable electronics.

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.

scholarly journals Clean one-pot multicomponent synthesis of pyrans using a green and magnetically recyclable heterogeneous nanocatalyst

SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki
Keyword(s):  
Room Temperature ◽  
Significant Loss ◽  
Copper Ferrite ◽  
Multicomponent Synthesis ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
One Pot ◽  
Three Component Reaction ◽  
Ft Ir ◽  
The One

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.

scholarly journals Synthesis of Magnetic Ferrocene-Containing Polymer with Photothermal Effects for Rapid Degradation of Methylene Blue

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng
Keyword(s):  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Degradation Rate ◽  
Model Compound ◽  
Vibrating Sample Magnetometer ◽  
Simulated Sunlight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.

scholarly journals Zirconium-Doped Chromium IV Oxide Nanocomposites: Synthesis, Characterization, and Photocatalysis towards the Degradation of Organic Dyes

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Solid State ◽  
Room Temperature ◽  
Organic Dyes ◽  
Uv Light ◽  
Heterogeneous Photocatalysis ◽  
Ft Ir ◽  
Complete Mineralization

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.

Ferroelectric Tunability Studies in Doped BaTiO3 and Ba1−xSrxTiO3

2000 ◽  
Vol 658 ◽  
Author(s):  
Dong Li ◽  
M. A. Subramanian
Keyword(s):  
Curie Temperature ◽  
Phase Change ◽  
Tetragonal Phase ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Co Doping ◽  
Structure Changes

ABSTRACTAcceptor and Donor codoped BaTiO3 and Ba1−xSrxTiO3 are prepared. For Ba1−xLaxTi1−xFexO3,BaTiO3 remains as tetragonal phase up to about 5mol% LaFeO3. For x ≥0.06, the structure changes to cubic at room temperature. The phase change shifts the Curie temperature to lower value and increases the tunability at room temperature. Doping of other acceptor (Al, Cr) and donor (Sm, Gd, Dy) ions has the same effect although with varying levels of tuning. BaTiO3: 4%LaFeO3 has the highest tunability among the studied systems, which is even higher than Ba0.6Sr0.4TiO3. Co-doping of (La, Fe) and (La, Al) in Ba1−xSrxTiO3 also lowers the Curie temperature and increases the tunability of high Ba content samples at cryogenic temperature.

Assessment of Magnetic Properties between Fe and Ni Doped ZnO Nanoparticles Synthesized by Microwave Assisted Synthesis Method

2021 ◽  
Vol 317 ◽  
pp. 119-124
Author(s):  
Sabiu Said Abdullahi ◽  
Garba Shehu Musa Galadanci ◽  
Norlaily Mohd Saiden ◽  
Josephine Ying Chyi Liew
Keyword(s):  
Magnetic Properties ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Synthesis Method ◽  
Dilute Magnetic Semiconductors ◽  
High Coercivity ◽  
Microwave Assisted Synthesis ◽  
Ferromagnetic Behavior ◽  
Microwave Assisted ◽  
Doped Zno

The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.

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