Effective magnetic susceptibility of suspensions of ferromagnetic particles
| Autor: | Aubrey Wahl, Joshua Casara, Florian Carle, Kunlun Bai, Eric Brown, Aparna Nair-Kanneganti |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Condensed matter physics Demagnetizing field General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Aspect ratio (image) Magnetic susceptibility Magnetic field Ferromagnetism 0103 physical sciences Particle Magnetic nanoparticles SPHERES 010306 general physics 0210 nano-technology |
| Zdroj: | Journal of Applied Physics. 124:123901 |
| ISSN: | 1089-7550 0021-8979 |
| Popis: | The effective susceptibility χeff of suspensions of ferromagnetic particles in a liquid was measured using inductance measurements. These measurements were used to test a model that predicts how χeff varies due to demagnetization, as a function of sample aspect ratio, particle packing fraction, and particle aspect ratio [R. Skomski, G. C. Hadjipanayis, and D. J. Sellmyer, IEEE Trans. Magn. 43, 2956–2958 (2007)]. For spherical particles or cylindrical particles forcibly aligned with an external magnetic field, the model can be fitted to the measured data with agreement within 13%. This model predicts suspensions of aligned, large-aspect-ratio particles should have the largest χeff, approaching the particle material susceptibility in the limit of large particle aspect ratio. However, χeff was found to be no larger than about 4 for cylindrical iron particles of various aspect ratios, close to the value obtained for spheres. This results from the random alignment of non-spherical particles relative to the magnetic field naturally found in suspensions, which increases the demagnetization effect and limits χeff. The contribution of random particle alignments to the demagnetization effect and χeff remains to be accounted for in models. |
| Databáze: | OpenAIRE |
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