The working principle of pot magnets cleverly exploits the unidirectional performance of magnets. While a regular magnet’s magnetic circuit is evenly distributed around it, combining it with ferromagnetic materials optimizes the performance of one side of the magnet.
Iron, being a ferromagnetic material, can be strongly magnetized by an external magnetic field and retain some magnetism after the field is removed. Moreover, ferromagnetic materials exhibit a hysteresis loop, meaning they do not immediately lose their magnetism upon demagnetization and require specific actions to be fully demagnetized. They also have a high magnetic permeability, effectively guiding magnetic field lines.
Therefore, when a magnetic iron case is combined with a magnet, it weakens the magnetic circuit on one side and strengthens it on the other. The working principle of pot magnets is to concentrate and enhance the magnetic field through this combination, thereby increasing the adhesive force.