scholarly journals Magnetic Properties and AC Losses in AFe2O4(A = Mn, Co, Ni, Zn) Nanoparticles Synthesized from Nonaqueous Solution

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Oleksandr Yelenich ◽  
Sergii Solopan ◽  
Taras Kolodiazhnyi ◽  
Yuliya Tykhonenko ◽  
Alexandr Tovstolytkin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Measurements ◽  
Spinel Ferrite ◽  
Blocking Temperature ◽  
Ac Losses ◽  
X Ray Diffraction ◽  
Average Magnetic Moment ◽  
Heating Efficiency ◽  
Cobalt Nickel ◽  
Transmission Electron

Nanosized particles of AFe2O4(A = Mn, Co, Ni, or Zn) spinel ferrites were synthesized by coprecipitation from nonaqueous solutions using nitrate salts as starting reagents. The particles were characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. Quasistatic magnetic measurements show superparamagnetic behavior with blocking temperature below room temperature for cobalt, nickel, and zinc spinel ferrite nanoparticles. Characteristic magnetic parameters of the particles including average magnetic moment of an individual nanoparticle and blocking temperature have been determined. The specific loss power which is released on the exposure of an ensemble of synthesized particles to a magnetic field is calculated and measured experimentally. It is shown that among all nanoferrites under study, the ZnFe2O4nanoparticles demonstrate the highest heating efficiency in AC magnetic fields. The key parameters responsible for the heating efficiency in AC magnetic field have been determined. The directions to enhance the SLP value have been outlined.

Magnetic cluster developement in In1−x MnxSb semiconductor alloys

Open Physics ◽  
2010 ◽  
Vol 8 (4) ◽  
Author(s):  
Lidia Rednic ◽  
Iosif Deac ◽  
Eugen Dorolti ◽  
Marin Coldea ◽  
Vasile Rednic ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Semiconductor Alloys ◽  
X Ray Diffraction ◽  
Magnetic Cluster ◽  
X Ray ◽  
Small Magnetic Field ◽  
Transmission Electron

AbstractX-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM) and magnetic measurements as a function of applied magnetic field and temperature for In1−x MnxSb (0.05≤x≤0.2) system are reported. Magnetic measurements performed at high and small magnetic field in ZFC and FC indicate the coexistence of ferromagnetic In1−x MnxSb solid solution and two types of magnetic cluster: ferromagnetic MnSb and ferrimagnetic Mn2Sb. XPS valence band and Mn 2p core level spectra have confirmed the presence of MnSb and Mn2Sb phases. TEM images show some manganese antimonide phase microinclusions with dimension between (30–40) nm.

Synthesis and Properties of Iron-Based Magnetic Nanoparticles

2016 ◽  
Vol 712 ◽  
pp. 282-287
Author(s):  
Nikita Sashko ◽  
Elena Vaitulevich ◽  
Tatiana Yurmazova
Keyword(s):  
Magnetic Field ◽  
Magnetic Measurements ◽  
Water Solution ◽  
Chemical Properties ◽  
Drug Carriers ◽  
Field Analysis ◽  
X Ray Diffraction ◽  
Magnetic Field Analysis ◽  
Transmission Electron ◽  
Physical And Chemical

We have obtained magnetite nanoparticles (MNP) by using chemical coprecipitation of Fe2+ and Fe3+ in water solution. The size of these particles was less than 9 nm, and they possessed corresponding physical and chemical properties. Citric acid was used to stabilize magnetite particles suspension. The acid was affixed to the surface of the particles by adding it in fresh MNP solution during synthesis. Affixing carboxyl groups on the surface of MNP not only does improve particles' dispersion in solvent, but also allows adding further modifications to their surface. The properties of the particles' microstructure and morphology were determined with X-Ray diffraction (XRD) and transmission electron microscopy (TEM), whereas their magnetic properties were determined by means of automated pulse magnetic field analysis equipment. Magnetic measurements have shown that saturation magnetization was 94 emu/g with nanoparticles being at room temperature. We have also researched possible application of these particles as drug carriers by determining doxorubicin sorption capacity on the surface of MNPs. These MNPs have proven to have perspective ability to be a magnetic field-controlled carrier for cancer-treating drugs. The obtained particles can also potentially be used as a contrast medium for MRI.

Synthesis and Magnetic Characterization of Nickel Ferrite Nanowire Arrays Doped with Manganese

2011 ◽  
Vol 233-235 ◽  
pp. 1799-1802 ◽  
Author(s):  
Jian Jun Gu ◽  
Li Hu Liu ◽  
Yun Kai Qi ◽  
Qin Xu ◽  
Hui Yuan Sun
Keyword(s):  
Nickel Ferrite ◽  
Magnetic Measurements ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Easy Magnetization ◽  
Magnetization Direction ◽  
Transmission Electron

The spinel ferrite system Ni1-xMnxFe2O4 (x = 0.0, 0.25, 0.5, 0.75) nanowire arrays with an average diameter of about 80 nm, have been synthesized into nanopores of anodic aluminum oxide (AAO) template using the sol–gel technique. X-ray diffraction analysis shows the formation of single-phase nickel manganese ferrites. Scanning electron microscopy and transmission electron microscope images indicate that the nanowire arrays are composed of prolate spheroids with different crystal orientations. Magnetic measurements show that the saturation magnetization (Ms) of nickel ferrite nanowire arrays is lower than that of bulk ones. But the Ms of the samples doped with Mn are greater than that of bulk ones. We do not observe obviously easy magnetization direction of all nanowire arrays. The possible reasons that are responsible for the composition dependence of the properties are discussed.

Mechanically Milled Co1-xFexO4 Nanocrystalline for Magnetic Hyperthermia Application

2019 ◽  
Vol 59 ◽  
pp. 25-34
Author(s):  
O.M Lemine ◽  
Sharif Abu Alrub
Keyword(s):  
Magnetic Field ◽  
Magnetic Measurements ◽  
Magnetic Hyperthermia ◽  
Annealed Sample ◽  
Alternating Magnetic Field ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Heating Efficiency ◽  
Powder Mass

Mechanical alloying of a mixture of Fe2O3 and CoO powders has been applied for the preparation of nanocrystalline. Utilizing a ball-to-powder mass ratio of 20, milling time of 20 hours followed by annealing at 900°C, we could obtain a nanocrystalline of high crystallinity and composed of mainly CoFe2O4 phase with presence of Fe2O3 as revealed by X-ray diffraction (XRD) measurements. Magnetic measurements using vibrating sample magnetometer (VSM) reveal high saturation magnetization for the annealed sample close to CoFe2O4 phase value. The heating efficiency of the obtained nanocrystalline is studied under an alternating magnetic field and as a function of the concentration. It was found that the nanocrystalline generate a substantial amount of heat when exposed to an alternating magnetic field. In vitro hyperthermia experiment was carried out and our result clearly demonstrates the ability of the obtained nanocrystalline to kill cancer cell through magnetic hyperthermia.

scholarly journals Dissimilatory Iron-Reducing Microorganisms Are Present and Active in the Sediments of the Doce River and Tributaries Impacted by Iron Mine Tailings from the Collapsed Fundão Dam (Mariana, MG, Brazil)

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 244
Author(s):  
Carolina N. Keim ◽  
Jilder D. P. Serna ◽  
Daniel Acosta-Avalos ◽  
Reiner Neumann ◽  
Alex S. Silva ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Magnetic Measurements ◽  
Culture Media ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferric Oxyhydroxide ◽  
Transmission Electron ◽  
Iron Mine ◽  
Organic Matter Oxidation ◽  
Doce River

On 5 November 2015, a large tailing deposit failed in Brazil, releasing an estimated 32.6 to 62 million m3 of iron mining tailings into the environment. Tailings from the Fundão Dam flowed down through the Gualaxo do Norte and Carmo riverbeds and floodplains and reached the Doce River. Since then, bottom sediments have become enriched in Fe(III) oxyhydroxides. Dissimilatory iron-reducing microorganisms (DIRMs) are anaerobes able to couple organic matter oxidation to Fe(III) reduction, producing CO2 and Fe(II), which can precipitate as magnetite (FeO·Fe2O3) and other Fe(II) minerals. In this work, we investigated the presence of DIRMs in affected and non-affected bottom sediments of the Gualaxo do Norte and Doce Rivers. The increase in Fe(II) concentrations in culture media over time indicated the presence of Fe(III)-reducing microorganisms in all sediments tested, which could reduce Fe(III) from both tailings and amorphous ferric oxyhydroxide. Half of our enrichment cultures converted amorphous Fe(III) oxyhydroxide into magnetite, which was characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The conversion of solid Fe(III) phases to soluble Fe(II) and/or magnetite is characteristic of DIRM cultures. The presence of DIRMs in the sediments of the Doce River and tributaries points to the possibility of reductive dissolution of goethite (α-FeOOH) and/or hematite (α-Fe2O3) from sediments, along with the consumption of organics, release of trace elements, and impairment of water quality.

scholarly journals Structural Evolution in Wet Mechanically Alloyed Co-Fe-(Ta,W)-B Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 800
Author(s):  
Vladimír Girman ◽  
Maksym Lisnichuk ◽  
Daria Yudina ◽  
Miloš Matvija ◽  
Pavol Sovák ◽  
...  
Keyword(s):  
Structural Changes ◽  
Magnetic Measurements ◽  
Structural Evolution ◽  
High Energy ◽  
Control Agent ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Transmission Electron ◽  
X Ray Absorption

In the present study, the effect of wet mechanical alloying (MA) on the glass-forming ability (GFA) of Co43Fe20X5.5B31.5 (X = Ta, W) alloys was studied. The structural evolution during MA was investigated using high-energy X-ray diffraction, X-ray absorption spectroscopy, high-resolution transmission electron microscopy and magnetic measurements. Pair distribution function and extended X-ray absorption fine structure spectroscopy were used to characterize local atomic structure at various stages of MA. Besides structural changes, the magnetic properties of both compositions were investigated employing a vibrating sample magnetometer and thermomagnetic measurements. It was shown that using hexane as a process control agent during wet MA resulted in the formation of fully amorphous Co-Fe-Ta-B powder material at a shorter milling time (100 h) as compared to dry MA. It has also been shown that substituting Ta with W effectively suppresses GFA. After 100 h of MA of Co-Fe-W-B mixture, a nanocomposite material consisting of amorphous and nanocrystalline bcc-W phase was synthesized.

Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

2007 ◽  
Vol 130 ◽  
pp. 171-174 ◽  
Author(s):  
Z. Stokłosa ◽  
G. Badura ◽  
P. Kwapuliński ◽  
Józef Rasek ◽  
G. Haneczok ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray ◽  
Second Stage ◽  
Transmission Electron

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

Fabrication, characterization and magnetic properties of Na-doped ZnO nanorods

2016 ◽  
Vol 09 (03) ◽  
pp. 1650039 ◽  
Author(s):  
Jingyuan Piao ◽  
Li-Ting Tseng ◽  
Kiyonori Suzuki ◽  
Jiabao Yi
Keyword(s):  
Magnetic Measurements ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Shallow Donors ◽  
Na Doping ◽  
Transmission Electron ◽  
Doped Zno ◽  
Electron Paramagnetic

Na-doped ZnO nanorods have been fabricated through a hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses indicate that the d spacing of ZnO increases with increasing doping concentration, suggesting the effective incorporation of dopant Na in the samples. Electron paramagnetic resonance (EPR) measurements indicate that there are shallow donors in pure ZnO samples and the shallow donors are strongly prohibited by Na doping. In addition, the resonance at g = 2.005 suggests the formation of Zn vacancies. Magnetic measurements indicate that pure ZnO is paramagnetic and Na doping leads to ferromagnetism at room temperature. Moreover, 0.5% Na-doped ZnO nanorods exhibits the largest saturation magnetization.

scholarly journals Effect of Alternating Magnetic Field on the Fatigue Behaviour of EN8 Steel and 2014-T6 Aluminium Alloy

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 984 ◽  
Author(s):  
Akram ◽  
Babutskyi ◽  
Chrysanthou ◽  
Montalvão ◽  
Pizurova
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Fatigue Behaviour ◽  
Alternating Magnetic Field ◽  
X Ray Diffraction ◽  
Secondary Precipitation ◽  
Transmission Electron ◽  
Fatigue Endurance ◽  
Fracture Features ◽  
Compressive Residual Stresses

The application of an alternating magnetic field (0.54 T) was observed to lead to an improvement in the fatigue endurance and an increase in Vickers microhardness and tensile strength of both EN8 steel and AA2014-T6 alloy. Fractography using scanning electron microscopy showed evidence of more ductile fracture features after treatment in contrast to untreated samples. The results of X-ray diffraction indicated formation of more compressive residual stresses following treatment; while examination by transmission electron microscopy showed evidence of fewer dislocations. In the case of the AA2014-T6 alloy; Guinier-Preston (GP) zones were also generated by the alternating magnetic field. However; the temperature increase during the treatment was too low to explain these observations. The results were attributed to the non-thermal effect of the alternating magnetic field treatment that led to depinning and movement of dislocations and secondary precipitation of copper.

Superconductivity of Dc Reactive Magnetron Sputtered Epitaxial TiN/NbN Superlattices

1992 ◽  
Vol 275 ◽  
Author(s):  
M. Shinn ◽  
B. -S. Hong ◽  
S. A. Barnett
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Surface ◽  
Wavelength Dependence ◽  
Reactive Magnetron ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

ABSTRACTEpitaxial B1-structure TiN/NbN superlattices have been grown by reactive magnetron sputtering On MgO(001). X-ray diffraction and transmission electron microscopy (TEM) diffraction spectra exhibited up to nine orders of superlattice reflections, indicating that the superlattice interfaces were relatively sharp. TEM images also showed well-defined layers. The superlattice wavelength (∧) dependence of the superconducting transition temperature (Tc), critical Current density (Jc), and electrical resistivity (ρ) have been investigated. Tc values increased from 12 K to 17 K with increasing ∧. Jc in a magnetic field perpendicular to the film surface ranged from 104 to 106 A/cm2, increasing with increasing wavelength and decreasing with increasing applied magnetic field. Jc in a field parallel to the film surface was > 10 times higher, ≈ 107 A/cm2. The resistivity exhibited different ∧ dependencies in three different A ranges.

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