Talk:Ferromagnetism
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There are a large number of pages that were gone over by someone last night, I think the one who signs himself "~ender", where links to orbitals were replaced by [[Electron configuration|orbitals]]. While I might prefer that the 'E' not be capitalized, I'm not going to make a big deal about it ;), but that article is much more relevant to discussion of orbitals than the orbit article is. -- John Owens 23:58 Apr 15, 2003 (UTC)
- The word "orbital" here is used as an adjective, not a noun. In this sense it refers to the circumferential motion of the electron around the nucleus. It is not a synonym for electronic configuration. It therefore seems misleading to write [[Electron configuration|orbitals]]. Although the orbit article is mostly about astronomy, it gives the appropriate definition for the term "orbital" as used in this case: "an orbit is the path that an object makes around another object under the influence of some force". -- Tim Starling 01:27 Apr 16, 2003 (UTC)
- Oh yeah, I guess so, ~ender may have painted with a bit too wide a brush. Given its relevance, though, we should probably find somewhere else to link it (if it isn't already). I'll work on that, if you haven't already. -- John Owens 01:34 Apr 16, 2003 (UTC)
- OK, electron shell is already linked in there, which redirects to electron configuration. That'll do just fine for me. -- John Owens 01:39 Apr 16, 2003 (UTC)
Can we maybe split the table into two pieces so it isn't too long? - Omegatron 22:57, Mar 23, 2004 (UTC)
- How about converting it to a vertical table which the text can flow around? -- Tim Starling 00:28, Mar 24, 2004 (UTC)
- Here's a vertical table...it's actually my original table, but I rotated it so that it would take less space (it was overwhelming the article). I didn't think to let the text flow around it; I'm not sure how to do that, actually, so knock yourself out. Steven G. Johnson 00:44, 24 Mar 2004 (UTC)
| Material | Curie temperature (K) |
|---|---|
| Fe | 1043 |
| Co | 1388 |
| Ni | 627 |
| Gd | 292 |
| Dy | 88 |
| MnAs | 318 |
| MnBi | 630 |
| MnSb | 587 |
| CrO2 | 386 |
| MnOFe2O3 | 573 |
| FeOFe2O3 | 858 |
| NiOFe23 | 858 |
| CuOFe2O3 | 728 |
| MgOFe23 | 713 |
| EuO | 69 |
| Y3Fe5O12 | 560 |
- I tried. It is not perfect, but it works for now. - Omegatron 17:24, Mar 24, 2004 (UTC)
- Thanks, it looks better. If someone could link the element names, that would be nice too. Steven G. Johnson 20:53, 24 Mar 2004 (UTC)
Bloch walls are only one type of domain boundary - Neel walls would be a second example. Perhaps this term could be changed to "Domain Wall" and Bloch/Neel walls listed as example?
Physical origins?
The Physical Origins section seems to state that ferromagnetism is caused by the "spin" momentum only, and clearly states that the effect of orbital angular momentum is to manifest diamagnetism. But Prof. Jerrold Franklin explains "The magnetic moment of the iron atom, which is responsible for ferromagnetism is due to the orbital anglar momentum of two outer electrons." [1] (http://www.madsci.org/cgi-bin/cgiwrap/www/circR?/posts/archives/2005-04/1113399101.Ph.r.html)
Can I get a 3rd opinion here?
- You're right...the article has suffered from a common shorthand in the physics literature (including in the Kittel reference cited). In Ashcroft and Mermin (Solid State Physics), they write: It is the widespread practice to refer to to the operators in the Heisenberg Hamiltonian [for ferromagnetism] as spin operators, even though the spin operator for each ion here represents its total angular momentum which, in general, has both a spin and an orbital part. It is still true that both ferromagnetism and paramagnetism require partially filled electron shells, of course, in order that their total moment be non-zero. I've fixed the article now, I think. —Steven G. Johnson 22:27, Apr 19, 2005 (UTC)