Английская Википедия:E. C. Stoner (physicist)

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Шаблон:Short description Шаблон:EngvarB Шаблон:Use dmy dates Шаблон:Infobox scientistEdmund Clifton Stoner FRS (2 October 1899 – 27 December 1968) was a British theoretical physicist. He is principally known for his work on the origin and nature of itinerant ferromagnetism (the type of ferromagnetic behaviour associated with pure transition metals like cobalt, nickel, and iron), including the collective electron theory of ferromagnetism and the Stoner criterion for ferromagnetism.[1][2][3][4][5][6] Stoner made significant contributions to the electron configurations in the periodic table.[7][8][9]

Biography

Stoner was born in Esher, Surrey, the son of cricketer Arthur Hallett Stoner. He won a scholarship to Bolton School (1911–1918) and then attended University of Cambridge in 1918, graduating in 1921. After graduation, he worked at the Cavendish Laboratory on the absorption of X-rays by matter and electron energy levels; his 1924 paper on this subject prefigured the Pauli exclusion principle.[10][11] Stoner was appointed a Lecturer in the Department of Physics at the University of Leeds in 1932, becoming Professor of Theoretical Physics in 1939. Starting in 1938, he developed the collective electron theory of ferromagnetism. From 1951 to 1963, he held the Cavendish Chair of Physics.[12] He retired in 1963.

He did some early work in astrophysics and independently computed the (Chandrasekhar) limit for the mass of a white dwarf[13] one year before Subrahmanyan Chandrasekhar in 1931.[14] Stoner calculation was based on earlier work from Wilhelm Anderson on the Fermi gas[15] and on earlier observations of Ralph H. Fowler on white dwarfs.[16][17] Stoner also derived a pressure–density equation of state for the stars in 1932.[18] These equations were also previously published by the Soviet physicist Yakov Frenkel in 1928. However Frenkel's work was ignored by the astronomical community.[19]

Stoner had been diagnosed with diabetes in 1919. He controlled it with diet until 1927, when insulin treatment became available.[20]

Stoner model of ferromagnetism

Шаблон:Main

Файл:Stoner model of ferromagnetism.svg
A schematic band structure for the Stoner model of ferromagnetism. An exchange interaction has split the energy of states with different spins, and states near the Fermi level are spin-polarized.

Electron bands can spontaneously split into up and down spins. This happens if the relative gain in exchange interaction (the interaction of electrons via the Pauli exclusion principle) is larger than the loss in kinetic energy.

<math>

\epsilon_{\uparrow} (k) = \epsilon_0 (k) - I \frac{n_{\uparrow}-n_{\downarrow}}{n} </math>

<math>

\epsilon_{\downarrow} (k) = \epsilon_0 (k) + I \frac{n_\uparrow-n_{\downarrow}}{n} </math> where <math>\epsilon_0 (k)</math> is the energy of the metal before exchange effects are included, <math>\epsilon_{\uparrow}</math> and <math>\epsilon_{\downarrow}</math> are the energies of the spin up and down electron bands respectively. The Stoner parameter which is a measure of the strength of the exchange correlation is denoted <math>I</math>, the number of electrons is <math> n = n_{\uparrow} + n_{\downarrow} </math>. Finally, <math> k </math> is the wavenumber as the electrons bands are in wavenumber-space. If more electrons favour one of the states, this will create ferromagnetism. The electrons obey Fermi–Dirac statistics so when the above formulas are summed over all <math>k</math>-space, the Stoner criterion for ferromagnetism can be established.

Awards and honors

Selected publications

Books

References

Шаблон:Reflist

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  1. ↑ Шаблон:Cite journal
  2. ↑ Шаблон:Cite journal
  3. ↑ Шаблон:Cite journal
  4. ↑ Шаблон:Cite journal
  5. ↑ Шаблон:Cite journal
  6. ↑ Шаблон:Cite journal
  7. ↑ Kragh, Helge. “Niels Bohr’s Second Atomic Theory.” Historical Studies in the Physical Sciences, vol. 10, University of California Press, 1979, pp. 123–86, https://doi.org/10.2307/27757389.
  8. ↑ Manjit Kumar, Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality, 2008.
  9. ↑ Шаблон:Cite journal
  10. ↑ Wolfgang Pauli. Exclusion principle and quantum mechanics. Online available via ⟨http://nobelprize.org⟩Шаблон:Dead link. Nobel Lecture delivered on December 13th 1946 for the 1945 Nobel Prize in Physics.
  11. ↑ Manjit Kumar, Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality, 2008.
  12. ↑ Шаблон:Cite web
  13. ↑ 13,0 13,1 Шаблон:Cite journal
  14. ↑ Шаблон:Cite journal
  15. ↑ Шаблон:Cite journal
  16. ↑ Шаблон:Cite journal
  17. ↑ Шаблон:Cite journal
  18. ↑ Шаблон:Cite journal
  19. ↑ Шаблон:Cite journal
  20. ↑ 20,0 20,1 Ошибка цитирования Неверный тег <ref>; для сносок frs не указан текст
  21. ↑ Шаблон:Cite journal
  22. ↑ Edmund Clifton Stoner, web page at the University of Leeds. Retrieved 21 December 2008.
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