Magnetic Materials (Ferromagnetic, Paramagnetic, Diamagnetic) - SS3 Physics Lesson Note

Materials can be classified into three categories based on their response to an external magnetic field: ferromagnetic, paramagnetic, and diamagnetic.

Ferromagnetic

Ferromagnetic materials are strongly attracted by a magnetic field and can retain their magnetization even after the field is removed. Examples of ferromagnetic materials include iron, nickel, cobalt, and their alloys. Ferromagnetism arises due to the alignment of the magnetic moments of the electrons in the material. In a ferromagnetic material, these magnetic moments are aligned in the same direction, resulting in a strong magnetic field.

Paramagnetic

Paramagnetic materials are weakly attracted by a magnetic field, and their magnetization disappears when the field is removed. Examples of paramagnetic materials include aluminium, platinum, and oxygen. Paramagnetism arises due to the presence of unpaired electrons in the material, which can align with an external magnetic field.

Diamagnetic

Diamagnetic materials are weakly repelled by a magnetic field, and their magnetization is opposite in direction to the applied field. Examples of diamagnetic materials include copper, silver, and gold. Diamagnetism arises due to the absence of unpaired electrons in the material, which causes a weak magnetic response.

The magnetic properties of a material are important in many practical applications, such as magnetic storage devices, magnetic sensors, and magnetic imaging. The ability to control the magnetic properties of materials is also crucial in the development of new technologies, such as spintronics, which use the spin of electrons in addition to their charge to process information.