Quantum Explanation of Magnets

[Hornbein]

How can a magnet be explained based on quantum properties? This seems like an obvious thing, but I can't find it online.

The best I can do on my own is that systems are at lower energy when the spins are aligned, so that's why magnets attract one another. The spin transfers angular momentum to remote charged particles, causing them to move in curved paths. But that's not right: there isn't any transfer because the angular momentum of the original particles remains unaffected. Or something like that.

 

[jtbell]

Have you seen the Wikipedia article on ferromagnetism?

http://en.wikipedia.org/wiki/Ferromagnetism

 

[Hornbein]

How can a magnet be explained based on quantum properties? This seems like an obvious thing, but I can't find it online.

The best I can do on my own is that systems are at lower energy when the spins are aligned, so that's why magnets attract one another. The spin transfers angular momentum to remote charged particles, causing them to move in curved paths. But that's not right: there isn't any transfer because the angular momentum of the original particles remains unaffected. Or something like that.

Richard Feynman says that there is no more fundamental explanation for a layman.

 

[Bill_K]

How can a magnet be explained based on quantum properties? This seems like an obvious thing, but I can't find it online.

The best I can do on my own is that systems are at lower energy when the spins are aligned, so that's why magnets attract one another. The spin transfers angular momentum to remote charged particles, causing them to move in curved paths. But that's not right: there isn't any transfer because the angular momentum of the original particles remains unaffected. Or something like that.

Associated with the spin of an electron is a magnetic dipole moment. As the article cited by jtbell says, interaction of the adjacent magnetic dipoles in some materials causes the spins to align, and a macroscopic magnetic field is produced.