What is diamagnetism?
The term diamagnetism refers to a physical phenomenon occurring in certain materials. It is a form of magnetism that often contrasts with paramagnetism and ferromagnetism. Diamagnetism is based on the properties of the electron shell of an atom and appears in materials that do not have permanent magnetic moments.
How does diamagnetism occur?
Fundamentally, diamagnetism is based on the interaction between an external magnetic field and the electrons in the atoms or molecules of a material. When an external magnetic field is applied, the electrons in the atoms or molecules of the diamagnetic material are affected. The electrons move inside the atoms or molecules in the opposite direction to the field direction due to the magnetic field.
This movement of the electrons creates a magnetic field that is opposite to the applied magnetic field. However, the resulting magnetic field of the diamagnetic material is very weak and shows no magnetic properties such as attraction or repulsion. Instead, the material is weakly repelled in an external magnetic field.
The cause of diamagnetism lies in the quantum mechanical nature of electron movement. When an external magnetic field is applied, the electrons in the atoms or molecules move in so-called quantum states, which are diamagnetic. The magnetic interaction of the electrons with the external magnetic field causes a shift in these quantum states, producing diamagnetic behavior.
Most materials exhibit some degree of diamagnetism, but in most cases this effect is very weak compared to other magnetic phenomena such as paramagnetism or ferromagnetism. Materials such as water, carbon compounds and noble gasses are typical examples of diamagnetic substances.
What are areas of application for diamagnetism?
In practice, diamagnetism can be used to study certain materials. By applying a strong magnetic field, one can use the diamagnetism properties of a material to gain information about its structural, magnetic or electronic properties. For example, diamagnetism measurement is widely used in solid state physics and chemistry to characterize materials.
