Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Electron spin on 30/09/2016 02:29:01
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I don't want answers like..."a magnet is magnetic bc it is metal or ferrous", or "magnets are magnets because they have 2 poles"..
Do we really know? IE: light can be suggested in the lab, that it has wave and particle properties..Hence the term duality.
Soooo. what makes a magnet, magnetic?
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Most magnetism has to do with the "spin" of subatomic particles. The effects of electron spin are vastly stronger than the effects of nuclear spin, so we will ignore that for the moment (though nuclear spin is essential for the performance of MRI and NMR instruments).
Electrons can either be "spin up" or "spin down." This has nothing to do with up and down, and could just as easily be left and right, or blue and red, but by convention they are up and down. Materials in which there are exactly as many spin up electrons as spin down electrons are called "diamagnetic," and are very weakly repelled by magnetic fields. Materials that have an imbalance in the number of spin up and spin down electrons are called "paramagnetic," have a net magnetic moment, and can interact with magnetic fields in much more interesting ways. Now things get tricky... there are several different ways that paramagnetic materials can be, depending on how the electrons interact with each other: ferromagnetic, ferrimagnetic and antiferromagnetic are the most common types, but there are other more exotic types of magnetism, especially when one starts considering rare earth elements, for which electrons can also have significant angular momentum about the nucleus, but I digress... Typical permanent magnets are ferromagnetic, which essentially means that all of the electrons align in such a way that the magnet has poles (this is a significant oversimplification, but perhaps a good starting point).
There are also electromagnets, which don't rely on the spin of electrons, but rather on the overall macroscopic motion of electrons.
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Most magnetism has to do with the "spin" of subatomic particles.
My thoughts also...
As a graduate lecturer and overall science peep for too many years, your answer was a reflection of my thoughts..Particularly the (electron) spin component with a dab of good ole' E-D-Haas angular momentum effect for fun.
I hope this Q has not been asked repeatedly, for I did not do a lot of digging...