Magnetic permeability disaccommodation in α-Fe-C-N and α-Fe-Al-C above room temperature

Magneto-impedance ratio of the multilayer [NiFe/Cu)]N study by the number of multilayer. The both sample films of NiFe and Cu are fabricated by electrodeposition methods on a Cu-patterned substrate. The characteristic of magneto-impedance (MI) is performed at room temperature. Magneto-impedance are modified by varying N times (2, 4, 6 and 8) and the measurements frequency. The result show that the typical symetry of the magneto-impedance curve. Then the magneto-impedance (MI) ratio increases with the increase of frequency and N number layers. The increase of the magnetic permeability should address the increase of the MI ratio. Finally, the highest magneto-impedance ratio of 13.79 is obtained for [NiFe (200)/Cu (25)]8 at frequency 100 kHz.

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Paramagnetic properties of a vacuum embedded in a strong magnetic field

Canadian Journal of Physics ◽

10.1139/p88-114 ◽

1988 ◽

Vol 66 (8) ◽

pp. 692-694 ◽

Cited By ~ 5

Author(s):

W. J. Mielniczuk ◽

D. R. Lamm ◽

S. R. Valluri

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Strong Magnetic Field ◽

Magnetic Permeability ◽

Room Temperature ◽

Paramagnetic Materials ◽

Paramagnetic Properties

It is shown that a vacuum embedded in a very strong magnetic field, B, behaves like an isotropic, paramagnetic medium. It is further demonstrated that the magnetic permeability μ(B) of the vacuum differs from 1 by not more than 1.1 × 10−4 for magnetic fields weaker than 4.4 × 1013 G (typical paramagnetic materials at room temperature have corresponding values in the range of 10−5–10−2).

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Large magnetic permeability and resonant frequency of CoFe nanofilms electrodeposited via optimizing plating solution parameters based on electrochemistry mechanisms

MRS Proceedings ◽

10.1557/opl.2014.486 ◽

2014 ◽

Vol 1708 ◽

Cited By ~ 1

Author(s):

BaoYu Zong ◽

YuPing Wu ◽

Nguyen Nguyen Phuoc ◽

Pin Ho ◽

FuSheng Ma

Keyword(s):

Resonant Frequency ◽

Magnetic Permeability ◽

Room Temperature ◽

Chemical Properties ◽

Microwave Properties ◽

Additive Concentration ◽

Salt Solutions ◽

Physico Chemical ◽

Plating Solution ◽

Solution Parameters

ABSTRACTA simple methodology to electrodeposit thin soft CoFe films with desirable microwave properties from simple salt solutions at room temperature is demonstrated. Plating solution parameters have diverse influences on real potentials of ion reductions and deposition behavior of the FeCo crystals, consequently affecting largely the particle size, crystal structure and chemical composition of the film fabricated. This in turn determines their static magnetism and dynamic microwave properties. Through optimizing solution additive, concentration and temperature from electrodeposition mechanism, the as-prepared nanofilms possess a low coercivity of < 30 Oe, moderate anisotropy of 60-90 Oe, high crystallinity and magnetic moment of ≥ 2.0 T, and hence readily display an ultrahigh magnetic permeability (up to 1128) and resonant frequency (up to 2.1 gigahertz) simultaneously, as well as other desirable physico-chemical properties. Thus the nanofilms can be applied to high gigahertz frequency applications.

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The effect of structural changes on magnetic permeability of amorphous powder Ni80Co20

Science of Sintering ◽

10.2298/sos0803303m ◽

2008 ◽

Vol 40 (3) ◽

pp. 303-309 ◽

Cited By ~ 3

Author(s):

A. Maricic ◽

M. Spasojevic ◽

S. Arnaut ◽

D. Minic ◽

M.M. Ristic

Keyword(s):

Magnetic Permeability ◽

Room Temperature ◽

Structural Changes ◽

Crystallization Rate ◽

Amorphous Powder ◽

Initial Time ◽

Time Interval ◽

Scanning Calorimetry ◽

Crystallization Peak ◽

Relative Magnetic Permeability

The structural changes of Ni80Co20 amorphous powder were tested during heating. The alloy was obtained by electrolysis from ammonia solution sulfate of cobalt and nickel on the titanium cathode. The differential scanning calorimetry (DSC) method was used to detect that the crystallization process of powder occurred in two stages with crystallization peaks temperatures of the first stage at 690 K and of the second stage at 790 K. The effect of structural relaxation and crystallization of powder on magnetic properties was predicted by measurement of the relative magnetic permeability change in isothermal and nonisothermal conditions. On the basis of the time change of relative magnetic permeability at a defined temperature in the temperature range of the first and second crystallization peak on the thermogram, the kinetics of crystallization was defined. It was predicted, that in the initial time interval, in the range of the first crystallization peak, the rate of crystallization is determined by the rate of nucleation of the amorphous part of the powder. However, in the second time interval, the crystallization rate is determined by the rate of diffusion. In the range of the second peak, in the beginning the rate of crystal growth is determined by activation energy of the atom pass from smaller to bigger crystal grain. In second time interval, the rate of crystal grain growth is determined by the diffusion rate of atoms to the location of integration into bigger crystal grains. For all processes which determine the rate of crystallization in temperature ranges of both crystallization peaks, the Arrhenius temperature dependence of rate for those processes is obtained. The relative magnetic permeability of crystallized powder at 873 K, is smaller for about 30 % than the relative magnetic permeability of fresh powder at room temperature. However, structurally relaxed powder at 573 K has an about 22 % larger magnetic permeability than the same fresh powder at room temperature.

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Dependence of Intergranular Fracture on Boundary Topography and Cohesion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071193 ◽

1973 ◽

Vol 31 ◽

pp. 150-151

Author(s):

J. E. Doherty ◽

A. F. Giamei ◽

B. H. Kear ◽

C. W. Steinke

Keyword(s):

Grain Boundary ◽

Room Temperature ◽

Nickel Base Superalloy ◽

Boundary Shear ◽

Room Temperature Ductility ◽

Solid Solution Matrix ◽

Nickel Base ◽

Solution Matrix ◽

Different Levels ◽

Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

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Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053085 ◽

1982 ◽

Vol 40 ◽

pp. 56-57

Author(s):

J. N. Turner ◽

D. N. Collins

Keyword(s):

Guinea Pigs ◽

Room Temperature ◽

Dose Group ◽

Methyl Cellulose ◽

Uranyl Acetate ◽

Target Organ ◽

Office Building ◽

Lead Citrate ◽

Control Groups ◽

Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

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Domain Formation in Synthetic Quartz

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064839 ◽

1971 ◽

Vol 29 ◽

pp. 156-157

Author(s):

Joseph J. Comer

Keyword(s):

Electron Beam ◽

Room Temperature ◽

Domain Formation ◽

Synthetic Quartz ◽

Transmission Electron ◽

Black Spots ◽

Diffraction Mode ◽

Domain Boundaries ◽

Kikuchi Lines ◽

Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

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A Liquid Nitrogen Cooled Stage for STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052237 ◽

1974 ◽

Vol 32 ◽

pp. 444-445

Author(s):

Louis T. Germinario

Keyword(s):

Electron Microscope ◽

High Resolution ◽

Liquid Nitrogen ◽

Room Temperature ◽

Objective Lens ◽

Thermal Drift ◽

Specimen Holder ◽

Resolution Capability ◽

Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

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Cryogenic atomic force microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084570 ◽

1991 ◽

Vol 49 ◽

pp. 54-55

Author(s):

K. A. Fisher ◽

M. G. L. Gustafsson ◽

M. B. Shattuck ◽

J. Clarke

Keyword(s):

Room Temperature ◽

Rapid Freezing ◽

Cryogenic Temperatures ◽

Soft Or ◽

Electrically Conductive ◽

Force Microscopy ◽

Flexible Molecules ◽

Advantages And Disadvantages ◽

Atomic Force ◽

Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

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