scholarly journals Magnetic flux density measurements from narrow grain boundaries produced in sintered permanent magnets

Microscopy ◽  
2020 ◽  
Author(s):  
Youngji Cho ◽  
Sujin Lee ◽  
Yasukazu Murakami
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Permanent Magnets ◽  
Thin Foil ◽  
Magnetic Flux Density ◽  
Electron Holography ◽  
Sintered Magnet ◽  
Density Measurements ◽  
Interface Magnetism

Abstract This review examines methods of magnetic flux density measurements from the narrow grain boundary (GB) regions, the thickness of which is of the order of nanometers, produced in Nd–Fe–B-based sintered magnets. Despite of the complex crystallographic microstructure and the significant stray magnetic field of the sintered magnet, recent progress in electron holography allowed for the determination of the intrinsic magnetic flux density due to the GB which is embedded in the polycrystalline thin-foil. The methods appear to be useful as well for intensive studies about interface magnetism in a variety of systems.

scholarly journals Magnetic flux density measurements from grain boundary phase in 0.1 at% Ga-doped Nd–Fe–B sintered magnet

2020 ◽  
Vol 178 ◽  
pp. 533-538 ◽  
Author(s):  
Youngji Cho ◽  
Taisuke Sasaki ◽  
Ken Harada ◽  
Atsuko Sato ◽  
Takehiro Tamaoka ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Magnetic Flux ◽  
Flux Density ◽  
Boundary Phase ◽  
Magnetic Flux Density ◽  
Sintered Magnet ◽  
Density Measurements

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

Platform Design for Characterizing Shear Force Produced by Magnetized Magnetorheological Fluid

2019 ◽  
Author(s):  
Ping-Hsun Lee ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Yield Stress ◽  
Flux Density ◽  
Shear Force ◽  
Permanent Magnets ◽  
Magnetic Flux Density ◽  
Finite Element Method Result ◽  
Mr Fluid ◽  
The Magnetic Field

Abstract In this paper we proposed a platform for measuring shear force of magnetorheological (MR) fluid by which the relationship of yield stress and magnetic flux density of specific material can be determined. The device consisted of a rotatable center tube in a frame body and the magnetic field was provided by two blocks of permanent magnets placed oppositely outside the frame body. The magnitude and direction of the magnetic field were manipulated by changing the distance of the two permanent magnets from the frame body and rotating the center tube, respectively. For determining the magnetic field of the device, we adopted an effective method by fitting the FEM (finite element method) result to the measured one and then rebuilt the absent components to approximate the magnetic field, which was hardly to be measured simultaneously as different device setup were required. With the proposed platform and analytical methods, the drawing shear force and the corresponding yield stress contributed by MR fluid could be evaluated in respect to the magnitude and direction of given magnetic flux density with acceptable accuracy for specific designing purposes without a large, complex, and expensive instrument.

scholarly journals Surface Magnetic Flux Density Patterning in EDM of Permanent Magnets

Procedia CIRP ◽  
2016 ◽  
Vol 42 ◽  
pp. 668-672 ◽  
Author(s):  
Hideki Takezawa ◽  
Naoki Hirakawa ◽  
Naotake Mohri
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Permanent Magnets ◽  
Magnetic Flux Density
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