Talk:Magnetism
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The origin of Magnetism is believed to be a consequence of general relativity. I'll have more to say/write in the article about this in a couple of weeks when I have access to my notes again.
from the article: "are iron, some steels, and the naturally occurring mineral lodestone?" Since steel is an alloy of iron, and loadstones contain iron, shouldn't the list of natural magnets be changed to "iron, nickle, and cobalt."
Lodestone contains iron, but only in the same way that salt contains chlorine: it is the particular way it contains iron that makes it magnetic. You could change it, but they're only examples - the only importance is that everyone will know what they are.
"Animal magnetism?" I had placed a mention of those idiotic magnetic "treatment" devices being sold at stores onto this page, and someone has changed it to "animal magnetism." If there is no objection, I'll change it back to "magnetic therapy" -- because is the popular name for this bogus "medical" treatment. -- Modemac
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Magnetism from electron spin
If magnetism comes from electron spin, why aren't all elements magnetic, as all elements have electrons? At least the ones, that are not full on the outer layer.
Can someone please elaborate on this? THANKS massa 13:50, 10 Jun 2004 (UTC)
I think that all elements that have unpaired electrons are paramagnetic. Ferromagnestism is a different kettle of fish though. ( I don't know enough about ferromagnetism to discuss it) theresa knott 13:54, 10 Jun 2004 (UTC)
- Electrons are divided into electron shells of different energies, with the lower energy levels filling up first. There are even numbers of electrons in each shell, and the electrons in each shell are paired to have spins that oppose each other (one is +.5, the other is -.5, every electron having a spin of magnitude one half, either + or -) so that the total spin of any filled shell is zero. That just leaves the last shell; if it is unfilled but has an even number of electrons, the total spin is again zero, no magnetism. If it has an odd number of electrons, there is an extra unpaired spin, which imparts to the whole atom a net spin of + or - .5. These are the paramagnetic elements, which are so weakly magnetic they are not normally thought of in the real world as magnetic, and require laboratory conditions to demonstrate any magnetic effect. (There are obviously many of them, though).
- What are normally in the real world thought of as magnetic elements are ferromagnetic metals: iron, cobalt and nickel, atomic numbers 26, 27, 28. With ferromagnetic metals, because the electron shells are large they have several subshells, and the requirement that all electron spins in the last shell except for maybe one odd electron are paired to oppose each other becomes a requirement that all electron spins in each subshell of the last shell except for maybe one odd electron are paired to oppose each other. That's the trick: unlike electron shells where the lower energy ones fill up first, the subshells are all in the same shell, and therefore at the same? or similarly close enough? energy levels that there can be several partially filled subshells, and there can be an odd number of electrons in each of these partially filled subshells, and these extra unpaired electrons in the subshells can all have the same spin; so that the total net spin for the atom can be several times + or - .5, therefore that many times the magnetic effect.
- Rare earth metals have the same thing happening in the next larger electron shell, with even more subshells, so they can have an even higher total net spin per atom than ferromagnetic metals, which is why they can be used for such powerful magnets. (This is a 30 year old memory of what was at the time a very good physics education, so take it for what it's worth). Gzuckier 16:08, 20 Aug 2004 (UTC)
- only 1 of the rare-earth elements is ferromagnetic. —Długosz 15:34, 8 Apr 2005 (UTC)
- That's still paramagnetism - you have a bunch of atoms with spins of several times .5, but the spins all point in random directions so they don't amount to much. In ferromagnetism nearby spins point in the same direction and their effect adds up. (The ferromagnetism article explains this better) Whether or not the spins line up depends on the type of atom(s), but also on arrangement of the atoms. For example, arrange iron in a BCC lattice and it's ferromagnetic, put it in an FCC one and it isn't. 131.203.9.226 08:08, 14 Jun 2005 (UTC)
Magnetic monopoles
Contrary to normal experience, theoretical physics predicts the existence of Magnetic monopoles.
Is this still true? Do we have any examples of this viewpoint later than 1931? anthony (see warning) 00:18, 20 Aug 2004 (UTC)
- Fang et al., The Anomalous Hall Effect and Magnetic Monopoles in Momentum Space, Science 2003 302: 92-95
- Jeon, H. and Longo, M. J. "Search for Magnetic Monopoles Trapped in Matter." Phys. Rev. Lett. 75, 1443-1446, 1995.
- Gzuckier 16:08, 20 Aug 2004 (UTC)
Magnetic Attraction
Anyone interested in explaining what is the property by which the two pieces of magnetic material are attracted to each other? For example, is the attractive force in the flux lines, or where? What brings them together? wojmax 27 sep, 04
Merging of Magnetism and Electromagnetism?
Shouldn't those 2 articles be merged and redirected as un the francophone wikipedia?
- Object. Magnetism and Electromagnetism are related topics which were discovered in a historical order. Gilbert built up a theory first (the Earth is a huge magnet). Electricity began to be understood 100 years afterward, with Maxwell unifying the theory 250 years after Gilbert. Further unifications are going on today. Magnetism as a concept is alive and well. Ancheta Wis 21:28, 5 Mar 2005 (UTC)