From where the energy of the magnetic field of the permanent magnet comes from ??

Question

I know its a phenomena , but just wondering ??

Answer 1

Magnetic domains within metals are in random fashion until they are placed in a strong magnetic field. When the domains are random the metal exhibits no magnetic properties. When exposed to an external magnetic field the domains align with the external field and depending on the material retentivity will maintain that alignment and become magnetized.
Demagnetization of most metals is performed with heat, vibration or exposure to a rapidly changing polarity field such as an AC current powered coil.

Answer 2

In its "natural" state, the permanent magnet is not - strictly speaking - magnetic.
There has to be something to "magnetize" the material ... kind of like using a natural magent to magnetize a needle to produe a compass. Except for the permanent magnet case, we need a large electromagnet to get the field density high enough.

Ultimately, the field of a permanent magnet comes from another (lesser) magnet, amplified through electricity.