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Title: Tomography based numerical simulation of the demagnetizing field in soft magnetic composites

The magneto-static behaviour of soft magnetic composites (SMCs) is investigated using tomography based direct numerical simulation. The microgeometry crucially affects the magnetic properties of the composite since a geometry dependent demagnetizing field is established inside the composite, which lowers the magnetic permeability. We determine the magnetic field information inside the SMC using direct numerical simulation of the magnetic field based on high resolution micro-computed tomography data of the SMC's microstructure as well as artificially generated data made of statistically homogeneous systems of identical fully penetrable spheres and prolate spheroids. Quasi-static electromagnetic behaviour and linear material response are assumed. The 3D magnetostatic Maxwell equations are solved using Whitney finite elements. Simulations show that clustering and percolation behaviour determine the demagnetizing factor of SMCs rather than the particle shape. The demagnetizing factor correlates with the slope of a 2-point probability function at its origin, which is related to the specific surface area of the SMC. Comparison with experimental results indicates that the relatively low permeability of SMCs cannot be explained by demagnetizing effects alone and suggests that the permeability of SMC particles has to be orders of magnitude smaller than the bulk permeability of the particle material.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. illwerke vkw Professorship for Energy Efficiency, Vorarlberg University of Applied Sciences, Hochschulstraße 1, 6850 Dornbirn (Austria)
  2. Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm (Sweden)
  3. Institute of Electrochemistry, Clausthal University of Technology, Arnold-Sommerfeld-Straße 6, 38678 Clausthal-Zellerfeld (Germany)
  4. Institute of Physical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck (Austria)
  5. Department of Mathematics, University of Innsbruck, Technikerstraße 13, 6020 Innsbruck (Austria)
Publication Date:
OSTI Identifier:
22402912
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; COMPARATIVE EVALUATIONS; COMPOSITE MATERIALS; COMPUTERIZED SIMULATION; COMPUTERIZED TOMOGRAPHY; FINITE ELEMENT METHOD; MAGNETIC FIELDS; MAGNETIC MATERIALS; MAGNETIC SUSCEPTIBILITY; MAXWELL EQUATIONS; MICROSTRUCTURE; PARTICLES; PERMEABILITY; SPECIFIC SURFACE AREA