Magnets have something called a curie temperature where they loose their magnetism. Is the loss permanent?

Answer 1

Yes.

Iron can be magnetized because every iron atom is like a tiny magnet. If the atoms in the iron are all jumbled around, their magnetic fields tend to cancel each other out, so the iron is not magnetized. But, by aligning all of the millions of atoms, their fields complement each other and a larger magnetic field is formed. This can be done by running the end of a strong magnet along a piece of raw iron repeatedly; try it with a nail or screwdriver. After thirty or forty times, you might notice that the nail or screwdriver will slightly attract other nails. Obviously, a magnet which can be so easily created can also easily lose its magnetism, so soft iron does not make very good magnets.

If you get the magnet hot enough, the atoms get scrambled about again, and the only way to re-magnetize it is to re-align the atoms.

Answer 2

First of all, you need to distinguish between two types of magnetism: ferromagnetism and permanent magnetism. The former means the material becomes magnetic only while in the presence of an external magnetic field (like an iron nail touching a permanent magnetic). A permanent magnet is one which maintains its magnetism regardless. Both properties are lost above the Curie point, but ferromagnetic susceptibility is generally recovered when the temperature drops again. A permanent magnet generally demagnetizes "permanently", at least until it's repolarized by, say, exposing it to an external magnetic field.

Answer 3

No. In magnets, electrons are aligned through a force called the exchange force. This alignment creates large domains of electrons to have all of their dipole moments aligned in the same direction. Raising the temperature causes the electrons to vibrate, rotate, etc. until the magnet goes through a phase transition where it is no longer magnetic. However, lower the temperature will allow the exchange forces to prevail again causing the magnetism to return.

Answer 4

depending on the length of exposure to this temperature the metal may lose its magnetism permanently. It is also dependent on the strength of the magnet to begin with. A stronger magnet can hold its force longer.

Answer 5

Yes, it is