An efficient algorithm for the reconstruction of the magnetization state within magnetic components is presented. The occurring inverse magnetostatic problem is solved by means of an adjoint approach, based on the Fredkin-Koehler method for the solution of the forward problem. Due to the use of hybrid FEM-BEM coupling combined with matrix compression techniques the resulting algorithm is well suited for large-scale problems. Furthermore the reconstruction of the magnetization state within a permanent magnet as well as an optimal design application are demonstrated.
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http://dx.doi.org/10.1038/srep40816 | DOI Listing |
In magnetoencephalography, linear minimum norm inverse methods are commonly employed when a solution with minimal a priori assumptions is desirable. These methods typically produce spatially extended inverse solutions, even when the generating source is focal. Various reasons have been proposed for this effect, including intrisic properties of the minimum norm solution, effects of regularization, noise, and limitations of the sensor array.
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January 2019
Department of Electrical and Computer Engineering, University of Akron, Akron, OH, 44325-3904, USA.
In this paper, micromagnetic analysis of an array of long magnetic nanowires (NWs) embedded in a nonmagnetic matrix is performed. It is found that for NWs with diameters on the order of a hundred nanometers, the anisotropy and exchange energies are negligible, so the total free energy is a sum of the Zeeman and magnetostatic energies. The minimum magnetostatic energy corresponds to the maximum Zeeman energy, whereby half of the NWs are magnetized parallel to the external field, while the rest of the NWs are magnetized antiparallel to the external fields.
View Article and Find Full Text PDFPhys Rev Lett
January 2018
National Laboratory of Solid State Microstructures, Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China.
We clarify the physical origin of the dc voltage generation in a bilayer of a conducting polymer film and a micrometer-thick magnetic insulator Y_{3}Fe_{5}O_{12} (YIG) film under ferromagnetic resonance and/or spin wave excitation conditions. The previous attributed mechanism, the inverse spin Hall effect in the polymer [Nat. Mater.
View Article and Find Full Text PDFSci Rep
March 2017
Department of Physics, The University of York, Heslington, York YO10 5DD, UK.
The generic problem of extracting information on intrinsic particle properties from the whole class of interacting magnetic fine particle systems is a long standing and difficult inverse problem. As an example, the Switching Field Distribution (SFD) is an important quantity in the characterization of magnetic systems, and its determination in many technological applications, such as recording media, is especially challenging. Techniques such as the first order reversal curve (FORC) methods, were developed to extract the SFD from macroscopic measurements.
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January 2017
Christian Doppler Laboratory of Advanced Magnetic Sensing and Materials, Institute of Solid State Physics, Vienna University of Technology, Austria.
An efficient algorithm for the reconstruction of the magnetization state within magnetic components is presented. The occurring inverse magnetostatic problem is solved by means of an adjoint approach, based on the Fredkin-Koehler method for the solution of the forward problem. Due to the use of hybrid FEM-BEM coupling combined with matrix compression techniques the resulting algorithm is well suited for large-scale problems.
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