What are permanent magnets? Give the ways for preparing them.

(N/A) Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets.
Methods for preparing permanent magnets:
$1$. Hammering: One can hold an iron rod in the north-south direction and hammer it repeatedly.
$2$. Stroking: One can hold an iron rod and stroke it with one end of a bar magnet a large number of times,always in the same sense.
$3$. Solenoid Method: An efficient way to make a permanent magnet is to place a ferromagnetic rod in a solenoid and pass a current through it. The magnetic field of the solenoid magnetises the rod.