Journal article
Expanding the Lorentz Concept in magnetism
- Abstract:
- In 1878, the Dutch physicist Hendrik Antoon Lorentz first addressed the calculation of the local electric field at an atomic site in a ferroelectric material, generated by all the other electric dipoles within the sample. This calculation, which applies equally well to ferromagnets, is taught in Universities around the World. Here we demonstrate that the Lorentz concept can be used to speed up calculations of the local dipolar field in square, circular, and elliptical shaped monolayers and thin films, not only at the center of the film, but across the sample. Calculations show that long elliptical and rectangular films should exhibit the narrowest ferromagnetic resonance linewidth. In addition, discrete dipole calculations show that the Lorentz cavity field (u 0M/3) does not hold in tetragonal films. Depending on the ratio (b/a), the local field can be either less/greater than (u 0M/3): an observation that has implications for ferromagnetic resonance. 3D simple cubic (SC) systems are also examined. For example, while most texts discuss the Lorentz cavity field in terms of a Lorentz sphere, the Lorentz cavity field still holds when a Lorentz sphere is replaced by a the Lorentz cube, but only in cubic SC, FCC and BCC systems. Finally, while the primary emphasis is on the discrete dipole-dipole interaction, contact is made with the continuum model. For example, in the continuous SC dipole model, just one monolayer is required to generate the Lorentz cavity field. This is in marked contrast to the discrete dipole model, where a minimum of five adjacent monolayers is required.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 2.1MB, Terms of use)
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- Publisher copy:
- 10.1088/1367-2630/ab2f63
Authors
- Publisher:
- IOP Publishing
- Journal:
- New Journal of Physics More from this journal
- Volume:
- 21
- Article number:
- 073063
- Publication date:
- 2019-07-30
- Acceptance date:
- 2019-07-04
- DOI:
- EISSN:
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1367-2630
- ISSN:
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1367-2630
- Keywords:
- Pubs id:
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pubs:1027056
- UUID:
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uuid:492a9e37-b329-423c-8b9d-26ec6477774f
- Local pid:
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pubs:1027056
- Source identifiers:
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1027056
- Deposit date:
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2019-07-04
Terms of use
- Copyright holder:
- Bowden et al
- Copyright date:
- 2019
- Notes:
- © 2019 The Author(s). Published by IOP Publishing Ltd on behalf of Deutsche Physikalische Gesellschaft and the Institute of Physics. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
- Licence:
- CC Attribution (CC BY)
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