Mössbauer Study of Microbial Synthesis of Iron-Containing Nanoparticles

2015 ◽  
Vol 233-234 ◽  
pp. 766-770
Author(s):  
A.A. Shapkin ◽  
N.I. Chistyakova ◽  
D.G. Zavarzina ◽  
T.N. Zhilina ◽  
V.S. Rusakov
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
External Magnetic Field ◽  
Wide Temperature Range ◽  
Room Temperature ◽  
Iron Reduction ◽  
Magnetic Moments ◽  
Microbial Synthesis ◽  
Mössbauer Studies ◽  
Average Size

Mössbauer studies of bioreduction products stabilized by acetone and ethanol were carried out at wide temperature range from 80 K to room temperature and in external magnetic field applied perpendicular to γ-beam at room temperature. The initial products (mixture of non-stoichiometric magnetite and maghemite) were formed during the iron reduction of synthesized ferrihydrite by bacterium G. ferrihydriticus. The addition of acetone and ethanol led to slight particle size decrease. The average size and magnetic moments were 11.2 nm and 524 µB, respectively.

scholarly journals Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

2016 ◽  
Vol 7 ◽  
pp. 990-994 ◽  
Author(s):  
Xiaoyu Li ◽  
Lijuan Sun ◽  
Hu Wang ◽  
Kenan Xie ◽  
Qin Long ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Firm Structure ◽  
Cobalt Nanowires ◽  
First Time

In contrast to the majority of related experiments, which are carried out in organic solvents at high temperatures and pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt nanowires are crystalline and mainly consist of cobalt as well as a small amount of platinum. Magnetic measurements showed that the resultant cobalt nanowires were ferromagnetic at room temperature. The saturation magnetization (M s) and the coercivity (H c) were 112.00 emu/g and 352.87 Oe, respectively.

scholarly journals Europium monoxide as a basis for creating a high-temperature spin injector in the semiconductor spintronics

2020 ◽  
Vol 6 (3) ◽  
pp. 113-123
Author(s):  
Arnold S. Borukhovich
Keyword(s):  
Magnetic Field ◽  
Solid Solution ◽  
Composite Material ◽  
High Temperature ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Spin Electronics ◽  
Wide Range ◽  
Semiconductor Spintronics ◽  
Europium Monoxide

The results of the creation of a high-temperature spin injector based on EuO: Fe composite material are discussed. Their magnetic, electrical, structural and resonance parameters are given in a wide range of temperatures and an external magnetic field. A model calculation of the electronic spectrum of the solid solution Eu–Fe–O, responsible for the manifestation of the outstanding properties of the composite, is performed. The possibility of creating semiconductor spin electronics devices capable of operating at room temperature is shown.

Viscomagnetic Heat Flux Experiments as a Test of Gas Kinetic Theory in the Burnett Regime

1978 ◽  
Vol 33 (7) ◽  
pp. 749-760 ◽  
Author(s):  
G. E. J. Eggermont ◽  
P. W. Hermans ◽  
L. J. F. Hermans ◽  
H. F. P. Knaap ◽  
J. J. M. Beenakker
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Heat Flux ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Flow Direction ◽  
Rectangular Channel ◽  
Gas Kinetic Theory ◽  
The Magnetic Field ◽  
Good Agreement

In a rarefied polyatomic gas streaming through a rectangular channel, an external magnetic field produces a heat flux perpendicular to the flow direction. Experiments on this “viscom agnetic heat flux” have been performed for CO, N2, CH4 and HD at room temperature, with different orientations of the magnetic field. Such measurements enable one to separate the boundary layer contribution from the purely bulk contribution by means of the theory recently developed by Vestner. Very good agreement is found between the experimentally determined bulk contribution and the theoretical Burnett value for CO, N2 and CH4 , yet the behavior of HD is found to be anomalous.

Infinite solitons in ferromagnetic materials with an internal magnetic field

2021 ◽  
pp. 2150413
Author(s):  
Hamdy I. Abdel-Gawad
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
External Field ◽  
Model Equation ◽  
Graphical Representation ◽  
Magnetic Moments ◽  
Soliton Solutions ◽  
Internal Magnetic Field ◽  
Multiple Soliton Solutions ◽  
The Magnetic Field

The ferromagnetism induced by an external magnetic field (EMF), in (3+1) dimensions, is governed by Kraenkel–Manna–Merle system (KMMS). A (1+1) dimension model equation was derived in the literature. The magnetic moments are parallel to the magnetic field in ferromagnetism as they are aligning in the same direction of the external field. Here, it is shown that the KMMS supports the presence of internal magnetic field. This may be argued to medium characteristics. The objective of this work is to mind multiple soliton solutions, which are obtained via the generalized together with extended unified methods. Graphical representation of the results are carried. They describe infinite soliton shapes, which arise from the multiple variation of the arbitrary functions in the solutions. It is, also, shown that internal magnetic field decays, asymptotically, to zero with time.

scholarly journals Room temperature giant magnetostriction in single-crystal nickel nanowires

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasios Pateras ◽  
Ross Harder ◽  
Sohini Manna ◽  
Boris Kiefer ◽  
Richard L. Sandberg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Three Dimensional ◽  
Local Strain ◽  
Nickel Nanowires ◽  
Giant Magnetostriction

Abstract Magnetostriction is the emergence of a mechanical deformation induced by an external magnetic field. The conversion of magnetic energy into mechanical energy via magnetostriction at the nanoscale is the basis of many electromechanical systems such as sensors, transducers, actuators, and energy harvesters. However, cryogenic temperatures and large magnetic fields are often required to drive the magnetostriction in such systems, rendering this approach energetically inefficient and impractical for room-temperature device applications. Here, we report the experimental observation of giant magnetostriction in single-crystal nickel nanowires at room temperature. We determined the average values of the magnetostrictive constants of a Ni nanowire from the shifts of the measured diffraction patterns using the 002 and 111 Bragg reflections. At an applied magnetic field of 600 Oe, the magnetostrictive constants have values of λ100 = −0.161% and λ111 = −0.067%, two orders of magnitude larger than those in bulk nickel. Using Bragg coherent diffraction imaging (BCDI), we obtained the three-dimensional strain distribution inside the Ni nanowire, revealing nucleation of local strain fields at two different values of the external magnetic field. Our analysis indicates that the enhancement of the magnetostriction coefficients is mainly due to the increases in the shape, surface-induced, and stress-induced anisotropies, which facilitate magnetization along the nanowire axis and increase the total magnetoelastic energy of the system.

Temperatur- und Konzentrationsabhängigkeit der 115In-Knightshift im flüssigen In-Mn-System

1990 ◽  
Vol 45 (7) ◽  
pp. 851-856
Author(s):  
I. Senel ◽  
D. Quitmann
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Moments ◽  
Metallic Alloys ◽  
Experimental Results

AbstractNMR measurements of the 115In-Knightshift and the linewidth in liquid In-Mn are reported. They were carried out in an external magnetic field of about 4.0 T at concentrations 0, 3, and 6 at.% Mn at temperatures from 400 K to 1300 K. According to our experimental results there are no localized magnetic moments in the liquid In-Mn-system. The experimental results are discussed in the framework of theories on metallic alloys.

Pyrochlores. IV. Crystallographic and Mössbauer studies of A2FeSbO7 pyrochlores

1968 ◽  
Vol 46 (24) ◽  
pp. 3829-3832 ◽  
Author(s):  
Osvald Knop ◽  
François Brisse ◽  
R. E. Meads ◽  
J. Bainbridge
Keyword(s):  
Magnetic Field ◽  
Oxygen Atom ◽  
Isomer Shift ◽  
Quadrupole Splitting ◽  
High Spin ◽  
Room Temperature ◽  
Magnetic Order ◽  
Standard Procedure ◽  
Hyperfine Magnetic Field ◽  
Mössbauer Studies

The lattice parameters and the quadrupole splittings of the room-temperature Mössbauer spectra of the cubic A2FeSbO7 pyrochlores (A = Sm, Eu, Gd, Tb, Y, Er, Lu) have been found to vary linearly with the Templeton–Dauben radii of the A3+ ions. The variation of the quadrupole splitting can be correlated with the positional parameter of the majority oxygen atom, x(O2), which determines the degree of distortion of the BO6 octahedron in cubic A2B2O7 pyrochlores. An increase of 0.1 Å in r(A3+) corresponds to a decrease of ca. 0.20 mm/s in the quadrupole splitting in the A2FeSbO7 series, and to an estimated increase of ca. 0.005 in x(O2). The isomer shift and quadrupole splitting at room temperature are typical of Fe3+(high spin) in octahedral coordination of relatively high distortion. Y2FeSbO7 at 4.2°K was found to exhibit magnetic order with a hyperfine magnetic field of approximately 400 kOe. An attempt to prepare a cubic La2FeSbO7, pyrochlore by the standard procedure was not successful.

Magnetic alignment in 2212 Bi-based superconducting system: Part I. Magnetic orientation of Bi2Sr2Ca1−x(RE)xCu2O8−y [(RE) = Gd, Dy, Ho, Er] powder dispersed in epoxy resin at room temperature

1996 ◽  
Vol 11 (5) ◽  
pp. 1082-1085 ◽  
Author(s):  
S. Stassen ◽  
R. Cloots ◽  
Ph. Vanderbemden ◽  
P. A. Godelaine ◽  
H. Bougrine ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
External Magnetic Field ◽  
Magnetic Anisotropy ◽  
Epoxy Resin ◽  
Room Temperature ◽  
Magnetic Alignment ◽  
Magnetic Orientation ◽  
System Part ◽  
The Rare Earth

The magnetic anisotropy of rare-earth substituted 2212 materials (Bi2Sr2Ca0.8RE0.2Cu2Ox with RE = Gd, Dy, Ho, Er) is put into evidence. Superconducting powder dispersed in epoxy resin is oriented under an external magnetic field (4 T) in a direction that depends on the nature of the rare-earth used in the substitution. Both directions of observation (parallel or perpendicular to the field) were investigated. Splitting of (00l) peaks is neatly observed and discussed.

Ferromagnetic Resonance On Metallic Glass Ribbons

2001 ◽  
Vol 674 ◽  
Author(s):  
M. Chipara ◽  
M. Toacsen ◽  
M. Sorescu
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Metallic Glass ◽  
Ferromagnetic Resonance ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Resonance Condition ◽  
X Band ◽  
Resonance Data

ABSTRACTFerromagnetic resonance data on metallic glasses, at room temperature, in X band, are discussed. The spectra were decomposed into two Lorentzian lines and the angular dependence of their main parameters (line width and position) is fully analyzed. It is proved that the usual approaches are not able to describe accurately the experimental data. This behavior is ascribed to the misalignment of the magnetization with respect to the external magnetic field, and successfully tested by using a “relaxed” resonance condition that allows a small misalignment of the magnetization relative to the external magnetic field.

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