Plus, he doesn't have much issue using whatever metal is near him. I think he bent a brass fountainpiece once, even though brass isn't magnetic. And the amount of control he can exercise seems like it's more than simple magnetism
The hammer is made from Uru, an Asgardian (metal? rock? No one really knows.). Uru is unique in that it absorbs energies, mostly magical, but it can absorb other types like radioactive, or electrical. So we can therefore assume that if Thor's hammer was to absorb electrical energy, which we often see it do when he calls down lightning, it would become magnetic, allowing Magneto to move it.
However, we must also consider the nature of Mjolnir itself. Mjolnir is a sentient fixed quantum point. That means that Mjolnir is a stubborn little shit who won't move unless it deems you worthy. So we must then ask the question: to Mjolnir, is Magneto worthy?
@gamzee there are several forms of magnetism, but we have never seen him use any form of magnetism other than Ferro-Magnetism (Mainly iron)
If you have nothing to do or would like to *try* to prove me wrong here is a link towards the different types: https://en.wikipedia.org/wiki/Magnetism#Materials
Obviously.
Who knows.
Anything can move Thor's hammer as long as a person is not.
So a magnet could pick up the hammer, but only if nobody was holding it.
If you have nothing to do or would like to *try* to prove me wrong here is a link towards the different types: https://en.wikipedia.org/wiki/Magnetism#Materials