why don't large magents repel themselves This question may have been asked before so I apologize in advance if it has.  I've been playing with some magnetic buckyballs I got recently (highly recommend getting some if you dont have any) and have had one question about magnetism I haven't been able to figure out.
I understand how N is attracted to S and N will repel N.  What I'm wondering is what prevents a large magnet from repelling itself.
Hypothetically you have a magnet that looks like this
[N][S]
and it makes sense that the N stays connected with the S, but what if you have a bigger magnet
[N][N][N][N][S][S][S][S]
what prevents the first two [N] or the last two [S] from repelling one another?  Is it just that the force from the other side carries all the way through?  Does this mean there is an upper limit to magnet size?
 A: A large magnet is indeed made up of lots of tiny magnets. In fact every unpaired electron in the material acts as a tiny bar magnet and the total field is made up by summing the individual magnetic fields of all these gazillions of electrons.
You are quite correct that if you place two bar magnets alongside each other with the north poles together then they will repel each other. This happens in most materials that have unpaired electrons and these materials are described as paramagnetic. They have no overall magnetic fields precisely because the electrons won't align their magnetic fields.
The sort of materials that you and I normally think of as magnetic are described as ferromagnets. In ferromagnets there is an extra interaction called an exchange force that overcomes the repulsion between the individual electron magnetic moments and allows them to align with each other. When this happens the individual magnetic fields reinforce each other and we get the macroscopic magnetic fields that we normally think of as magnets.
A: The story about designed permanent magnets starts with the creation of such magnets. One take materials - often including rare earth materials - with hight magnetic dipole moments and make a powder from this material. Before starting to sinter this material it will be switched on a strong magnetic field that aligns the before chaotic distributed magnetic dipole moments. One transfer energy into this alignment. Therefore the sintered magnetic is under inner tensions.
This one can see easy by dropping the magnet on the floor. Don't do this or be very careful in the case of strong magnets! So the unpaired electrons are aligned in a "chain" north-south-north-south-.... but the molecules are not in equilibration.
