In the applied magnetic field, the material can exhibit three kinds of conditions: 1 is not attracted by the magnetic field, called diamagnetic material; 2 is weakly attracted by the magnetic field, called paramagnetic material; 3 is strongly attracted by the magnetic field, said iron Magnetic materials, whose magnetic properties increase sharply with the strengthening of the external magnetic field, and retain magnetic properties after the external magnetic field is removed. Among metal materials, most transition metals have paramagnetism; only a few metals such as Fe, Co, and Ni are ferromagnetic.
The main elements that make up the permanent magnet material in the metal are Fe, Co, Ni and certain rare earth elements. The permanent magnet alloys used are rare earth cobalt, iron chromium, cobalt and manganese aluminum alloys.
Magnetic alloys are increasingly used in emerging technologies such as power, electronics, computers, automation, and electro-optics.