Edmund Clifton StonerFRS (2 October 1899 – 27 December 1968) was a British theoreticalphysicist. He is principally known for his work on the origin and nature of itinerantferromagnetism (the type of ferromagnetic behaviour associated with pure transition metals like cobalt, nickel, and iron), including the collective electron theory offerromagnetism and theStoner criterion forferromagnetism.^{[3][4][5][6][7][8]} Stoner made significant contributions to the electron configurations in theperiodic table.^[9][10][11]

Stoner was born in Esher, Surrey, the son of cricketerArthur Hallett Stoner. He won a scholarship toBolton School (1911–1918) and then attendedEmmanuel College, Cambridge, graduating with a degree in natural sciences in 1921.^[12] After graduation, he worked at theCavendish Laboratory on the absorption ofX-rays by matter andelectron energy levels; his 1924 paper on this subject prefigured thePauli exclusion principle.^[13][10] Stoner was appointed a Lecturer in the Department ofPhysics at theUniversity of Leeds in 1932, becoming Professor of Theoretical Physics in 1939. Starting in 1938, he developed the collective electron theory offerromagnetism. DuringWWII he collaborated with his studentE. P. Wohlfarth and P. Rhodes on the development of high-coercivity magnetic materials fornewly-developed magnetrons and managed the university department while the official head was seconded to government service away from the Leeds.^[14] From 1951 to 1963, he held the Cavendish Chair of Physics.^[15] He retired in 1963.

He did some early work inastrophysics and independently computed the(Chandrasekhar) limit for the mass of awhite dwarf^[16] one year beforeSubrahmanyan Chandrasekhar in 1931.^[17] Stoner calculation was based on earlier work fromWilhelm Anderson on theFermi gas^[18] and on earlier observations ofRalph H. Fowler on white dwarfs.^[19][20] Stoner also derived apressure–densityequation of state for the stars in 1932.^[21] These equations were also previously published by theSovietphysicistYakov Frenkel in 1928. However, Frenkel's work was ignored by the astronomical community.^[22]

Stoner had been diagnosed withdiabetes in 1919. He controlled it with diet until 1927, wheninsulin treatment became available.^[1]

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

${\displaystyle {ϵ}_{\uparrow }(k)={ϵ}_0(k)-I\frac{n_{\uparrow }-n_{\downarrow }}{n}}$

${\displaystyle {ϵ}_{\downarrow }(k)={ϵ}_0(k)+I\frac{n_{\uparrow }-n_{\downarrow }}{n}}$

where${\displaystyle {ϵ}_0(k)}$ is the energy of the metal before exchange effects are included,${\displaystyle {ϵ}_{\uparrow }}$ and${\displaystyle {ϵ}_{\downarrow }}$ 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${\displaystyle I}$, the number of electrons is${\displaystyle n=n_{\uparrow }+n_{\downarrow }}$. Finally,${\displaystyle k}$ is thewavenumber as the electrons bands are in wavenumber-space. If more electrons favour one of the states, this will create ferromagnetism. The electrons obeyFermi–Dirac statistics so when the above formulas are summed over all${\displaystyle k}$-space, theStoner criterion for ferromagnetism can be established.

• He was elected aFellow of the Royal Society in May 1937.^[23]
• The E.C. Stoner building at theUniversity of Leeds is named after him.^[1][24]

• Stoner, Edmund C. (1924). "LXXIII. The distribution of electrons among atomic levels".The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science.48 (286):719–736.doi:10.1080/14786442408634535.ISSN 1941-5982.
• Stoner, Edmund C. (1929). "V.The limiting density in white dwarf stars".The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science.7 (41):63–70.doi:10.1080/14786440108564713.ISSN 1941-5982.^[16]
• Stoner, Edmund C. (1930). "LXXXVII.The equilibrium of dense stars".The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science.9 (60):944–963.doi:10.1080/14786443008565066.ISSN 1941-5982.
• Stoner, Edmund C. (1951)."Collective electron ferromagnetism in metals and alloys".Journal de Physique et le Radium.12 (3):372–388.doi:10.1051/jphysrad:01951001203037200.S2CID 33136356.

• Stoner, Edmund Clifton (1956).Magnetism and Atomic Structure. Methuen & Company Limited.
• Stoner, Edmund Clifton (1934).Magnetism and Matter. Methuen.

• 1899 births
• 1968 deaths
• People from Esher
• English physicists
• Academics of the University of Leeds
• People educated at Bolton School
• Alumni of Emmanuel College, Cambridge
• 20th-century British physicists
• British fellows of the Royal Society

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