Physicists believe that ferromagnetic materials like iron have many unmatched electrons inside. When an external magnetic field is applied to them, they will be "magnetized", and the manifestation of magnetization is that they can be attracted by a magnet.

Magnets are the most common thing in our lives, but if we want to explain magnetism, general theories are not enough. Even if you call Newton, he may not be able to explain the cause of magnetic force in magnets. Only quantum mechanics can do it.

We know that there are four fundamental forces in the universe, and electromagnetic force is one of them. Electromagnetic force can be decomposed into magnetic force and Coulomb force, both of which have the same goal. Magnetic force is a "Coulomb force" generated by moving charges.

The fundamental component of all common substances is atoms, and the composition of atoms includes nuclei and electrons. Electrons move around atomic nuclei according to quantum mechanics, and they have fixed orbitals. The motion of electrons will have an external effect, which is the magnetic moment. When the movement of electrons within the atoms of a substance is very uniform and coordinated, the magnetic moment generated by the movement of electrons will be largely cancelled out, resulting in no external magnetism or only weak magnetism. And the atoms in the middle of the periodic table have an uneven distribution of electrons, leading to the occurrence of magnetism.

But the magnetism possessed by magnets is not present in all the atoms in the periodic table of these elements. Having a magnetic moment is just a small step at the beginning, and the atoms that make up matter are not limited to millions. These atoms will randomly arrange and combine, ultimately leading to a significant cancellation of their magnetism. Only substances with special crystal structures will form magnetic domains within the crystal, and atoms within these crystals will exhibit high magnetism. When they encounter a magnetic field, these magnetic domains will act and exhibit magnetism in the same direction in the magnetic field. When the magnetic field disappears, these magnetic domains even maintain a certain degree of magnetic force, which is a common artificial permanent magnet in our daily lives. They have already been magnetized.

In addition to iron, cobalt and nickel are also more easily magnetized. In many electronic products, we can find such a small permanent magnet.