DOI: 10.1063/1.1656363. The Fundamental Theorem of Fine-Ferromagnetic-Particle Theory

The Fundamental Theorem of Fine-Ferromagnetic-Particle Theory

10.1063/1.1656363

Crossref journal-article

AIP Publishing

Journal of Applied Physics (317)

Abstract

The theory of fine-particle magnets is based on the theorem that the state of lowest free energy of a ferromagnetic particle is one of uniform magnetization for particles of less than a certain critical size and one of nonuniform magnetization for larger particles. The theorem is inferred from several approximate calculations and has not been proved rigorously. Rigorous statements can be made if one is content to replace equalities by inequalities and exact values of critical radii by upper and lower bounds. For a sphere of radius a with uniaxial anisotropy, it can be shown that the lowest-free-energy state is one of uniform magnetization if a&lt;ac0 and one of nonuniform magnetization if a&gt;ac1 (for low anisotropy) or ac2 (for high anisotropy), where ac0, ac1 (&gt;ac0), and ac2(&gt;ac0) are determined by the exchange and anisotropy constants and the spontaneous magnetization. These bounds locate the critical radius to within about 12% at low anisotropy but only to within an order of magnitude or more at high.

Bibliography

Brown, W. F. (1968). The Fundamental Theorem of Fine-Ferromagnetic-Particle Theory. Journal of Applied Physics, 39(2), 993â994.

Authors 1

William Fuller Brown (first)

References 7 Referenced 164

{'key': '2024020210353665100_r1'}
10.1103/RevModPhys.21.541 / Rev. Mod. Phys. (1949)
{'key': '2024020210353665100_r3'}
10.1063/1.1702798 / J. Appl. Phys. (1964)
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{'key': '2024020210353665100_r6'}
{'key': '2024020210353665100_r7'}

Dates

Type	When
Created	21 years, 6 months ago (Feb. 9, 2004, 11:55 a.m.)
Deposited	1 year, 7 months ago (Feb. 2, 2024, 6:10 a.m.)
Indexed	5 months ago (April 3, 2025, 8:38 p.m.)
Issued	57 years, 7 months ago (Feb. 1, 1968)
Published	57 years, 7 months ago (Feb. 1, 1968)
Published Print	57 years, 7 months ago (Feb. 1, 1968)

Funders 0

None

BibTeX

@article{Brown_1968, title={The Fundamental Theorem of Fine-Ferromagnetic-Particle Theory}, volume={39}, ISSN={1089-7550}, url={http://dx.doi.org/10.1063/1.1656363}, DOI={10.1063/1.1656363}, number={2}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Brown, William Fuller}, year={1968}, month=feb, pages={993–994} }

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