Magnet which is formed naturally is called natural magnet. Man- made magnets are called artificial magnet. For instance, Bar magnet, U-shaped magnet, etc.
The molecules of the magnetic substance retain the magnetic property. They are known as molecular magnets.
The poles of a magnet cannot be separated even by breaking into pieces because they exist in a pair, every molecule of a magnet has poles in a pair.
A magnet has molecules aligned in the same direction which provides it the magnetic property.
The molecular magnets are arranged in an open chain so that the north pole or the south pole of the molecular magnets lie in the same direction which gives strong force at the poles whereas two opposite poles are arranged at the middle and the force cancel each other. So, poles have more force than the middle portion.