scholarly journals A method of determining the highest temperature attained by magnetic material in the adiabatic magnetization

2012 ◽  
Vol 61 (9) ◽  
pp. 097501
Author(s):  
Chen Hui ◽  
Zhang Guo-Ying ◽  
Yang Dan ◽  
Gao Jiao
Author(s):  
K. Shi rota ◽  
A. Yonezawa ◽  
K. Shibatomi ◽  
T. Yanaka

As is well known, it is not so easy to operate a conventional transmission electron microscope for observation of magnetic materials. The reason is that the instrument requires re-alignment of the axis and re-correction of astigmatism after each specimen shift, as the lens field is greatly disturbed by the specimen. With a conventional electron microscope, furthermore, it is impossible to observe magnetic domains, because the specimen is magnetized to single orientation by the lens field. The above mentioned facts are due to the specimen usually being in the lens field. Thus, special techniques or systems are usually required for magnetic material observation (especially magnetic domain observation), for example, the technique to switch off the objective lens current and Lorentz microscopy. But these cannot give high image quality and wide magnification range, and furthermore Lorentz microscopy is very complicated.


2019 ◽  
Vol 139 (2) ◽  
pp. 84-87
Author(s):  
Kentaro MORI ◽  
Masahiko WATANABE
Keyword(s):  

Author(s):  
Ines Gilch ◽  
Tobias Neuwirth ◽  
Benedikt Schauerte ◽  
Nora Leuning ◽  
Simon Sebold ◽  
...  

AbstractTargeted magnetic flux guidance in the rotor cross section of rotational electrical machines is crucial for the machine’s efficiency. Cutouts in the electrical steel sheets are integrated in the rotor sheets for magnetic flux guidance. These cutouts create thin structures in the rotor sheets which limit the maximum achievable rotational speed under centrifugal forces and the maximum energy density of the rotating electrical machine. In this paper, embossing-induced residual stress, employing the magneto-mechanical Villari effect, is studied as an innovative and alternative flux barrier design with negligible mechanical material deterioration. The overall objective is to replace cutouts by embossings, increasing the mechanical strength of the rotor. The identification of suitable embossing geometries, distributions and methodologies for the local introduction of residual stress is a major challenge. This paper examines finely distributed pyramidal embossings and their effect on the magnetic material behavior. The study is based on simulation and measurements of specimen with a single line of twenty embossing points performed with different punch forces. The magnetic material behavior is analyzed using neutron grating interferometry and a single sheet tester. Numerical examinations using finite element analysis and microhardness measurements provide a more detailed understanding of the interaction of residual stress distribution and magnetic material properties. The results reveal that residual stress induced by embossing affects magnetic material properties. Process parameters can be applied to adjust the magnetic material deterioration and the effect of magnetic flux guidance.


2013 ◽  
Vol 543 ◽  
pp. 35-38 ◽  
Author(s):  
Masaaki Futamoto ◽  
Tatsuya Hagami ◽  
Shinji Ishihara ◽  
Kazuki Soneta ◽  
Mitsuru Ohtake

Effects of magnetic material, coating thickness, and tip radius on magnetic force microscope (MFM) spatial resolution have been systematically investigated. MFM tips are prepared by using an UHV sputtering system by coating magnetic materials on non-magnetic Si tips employing targets of Ni, Ni-Fe, Co, Fe, Fe-B, and Fe-Pd. MFM spatial resolutions better than 9 nm have been confirmed by employing magnetic tips coated with high magnetic moment materials with optimized thicknesses.


2013 ◽  
Vol 774-776 ◽  
pp. 907-912
Author(s):  
Hui Bin Zhang ◽  
Li Wei Deng ◽  
Nan Zhang ◽  
Pei Heng Zhou ◽  
Jian Liang Xie ◽  
...  

We simulate, fabricate and measure a microwave absorber by introducing metamaterial design method to magnetic material. The proposed absorber is composed of periodic copper wire array, magnetic material coated on copper wires, a foam substrate and a bottom metal plane. The results show a nearly perfect absorption peak around 8.7GHz (simulated) and 7.6GHz (measured). Even though the electric and magnetic field distribution indicate that the absorption is a typical metamaterial absorption, the power loss is neither Ohmic nor dielectric loss but magnetic loss, which is different from typical metamaterial absorber. The skillful introduction of the magnetic loss improves the absorption performance, including the absorption bandwidth and intensity. The designed absorber shows an effective application of the magnetic material, which is only 1/60000 volume proportion of the total absorber. Dependences of the absorption on frequency and the coating volume of the magnetic material manifest that the coated magnetic material can adjust the absorption peak position and intensity. The absorber can be an attractive candidate of electromagnetic wave absorber.


2014 ◽  
Vol 685 ◽  
pp. 314-319
Author(s):  
Hong Yang ◽  
Dan Liu ◽  
Wei Chen

Based on the magnetic materials (JV-5) substrate, Double L-shaped slot microstrip antenna is designed. The bandwidth is over 2 times that of the normal substrate and a 40% reduction in size happens.. On this basis, the microstrip antenna with magnetic substrate EBG structure is designed and the EBG structure uses the corrosive effects of joint floor, namely getting periodic H-shaped and circular structures by the floor corrosion, and performing a simulation with HFSS14.0. The results show that the EBG structure of magnetic material having a prominent advantage of the miniaturization and bandwidth-broaden compared to a microstrip antenna with non-magnetic materials substrate, resulting in more than 10% relative bandwidth and a slight gain loss. To some degree, introducing EBG structure can reduce the size of the antenna and increase its bandwidth, and it also improve the gain and radiation characteristics of the antenna.Key words: EBG structure; magnetic material;Double L-shaped slot microstrip antenna; gain


RSC Advances ◽  
2014 ◽  
Vol 4 (43) ◽  
pp. 22606-22612 ◽  
Author(s):  
R. P. Pogorilyi ◽  
I. V. Melnyk ◽  
Y. L. Zub ◽  
S. Carlson ◽  
G. Daniel ◽  
...  

Magnetic material stable to acid leaching was produced by silica coating of byproduct from the industrial synthesis of alkali iodides.


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