A wire is wound around an iron core. A current flowing through the wire coil produces its own magnetic field and magnetizes the iron. The magnetic field produced by the iron is much stronger than the field produced by the current in the coil. Typically an iron core magnifies the field by a factor of 100 to 1000. When the current in the coil is reduced to zero, the soft iron core looses its magnetization.
Magnetic effects are temperature sensitive.
At higher temperatures the atoms in the material have a higher average kinetic energy, and it is easier for interactions to misalign the spins. Above a critical temperature known as the Curie temperature , ferromagnets lose their ferromagnetic properties. Forces between magnets Macroscopically, magnets act like current loops. The internal currents of the electrons produce a net magnetization current flowing along the surface of the material. In an external magnetic field produced by another magnet or by a current flowing in a wire, magnets are therefore acted on by forces and torques.