Electric and magnetic fields are closely related but follow different laws in practice. While electric charges are described as positive or negative, the poles of a magnet are referred to as the north pole and the south pole. North and south poles of different magnets attract each other, while like poles repel.
Magnetic field lines, unlike electric field lines, are always closed loops. This means that no naturally occurring magnetic charges exist. Free magnetic monopoles, which would be the magnetic analog of a single electric charge with only a north or a south pole, have not yet been experimentally observed.
In a bar magnet, the field lines outside the magnet run from the north pole to the south pole. Inside the magnet, however, they must run from the south pole back to the north pole to form closed loops. If a magnet is cut in half, two new magnets are formed, each with its own north and south pole.