Diamagnetism: Materials and Magnetic Properties
by Yuvi K - December 17, 2023
Diamagnetism – An Overview
Diamagnetism is one of the four fundamental types of magnetism that exist in the world around us. It is a type of magnetic response to an external magnetic field that occurs in all materials. When exposed to a magnetic field, the material either repels or remains neutral, instead of being attracted like ferromagnetic materials. Diamagnetic materials are repelled away from an external magnetic field.
Diamagnetism has several properties that differentiate it from the other three types of magnetism, ferromagnetism, paramagnetism, and antiferromagnetism. It is especially useful for researchers interested in studying the magnetic properties of materials, as well as for everyday applications such as shielding and cooling.
Properties of Diamagnetism
The two main properties of diamagnetism are the weak magnetic response and the degree of repulsion from an external field. Diamagnetic materials are generally characterized by very weak magnetism, as they only produce a magnetic field when exposed to an external field. This means that they have very low magnetic susceptibilities. The degree of repulsion from the external field is also weak, as diamagnetic materials are typically repelled more weakly than other materials. Diamagnetic materials are repulsed by both magnetic and non-magnetic materials.
Examples of Diamagnetic Materials
Diamagnetic materials are found in nature and are used in a variety of applications. Common examples of diamagnetic materials include water, carbon, bismuth and pyrolusite. Other elements, such as oxygen and nitrogen, can also show diamagnetic behaviour in certain conditions.
In addition to naturally-occurring diamagnetic materials, there are also a number of man-made materials that exhibit diamagnetism. These materials are typically made of a combination of carbon and other diamagnetic materials, such as bismuth or copper. Man-made diamagnetic materials are often used in the construction of magnetic shields and in the cooling of superconductors.
Table 1 – Some Magnetic Properties of Diamagnetic Materials
| Material | Magnetic Susceptibility (χ) | Magnetic Field (B) | Magnetic Moment (μ) |
|---|---|---|---|
| Bismuth (Biswas) | -0.3 to -0.7 | 0.8-4.0 | 0.0083 |
| Pyrolusite (PJL) | -0.6 | 2.0 | -0.083 |
| Oxygen (Swasthya) | -2.5 to -3.5 | 1.4-13.9 | -0.05 |
| Nitrogen (Dhulai) | -90 to -85 | 18 to 33 | -0.2 |
Applications of Diamagnetic Materials
Diamagnetic materials have various applications in various fields. They can be used to make magnetic shields, which reduce the effects of an external magnetic field on electronic components. Diamagnetic materials can also be used for levitation, as they can be suspended and manipulated by external magnetic fields. They can also be used for cooling, as they repel the heat produced by the external source.
In addition to these more specialized applications, diamagnetic materials are also used in everyday life, such as in magnetic resonance imaging (MRI) machines. MRI scans use diamagnetic materials to create three-dimensional images of the body. Diamagnetic materials are also used to make jewelry and trinkets, such as magnetic bracelets, rings and earrings.
Conclusion
Diamagnetism is one of four fundamental types of magnetism. It is characterized by very weak magnetism and a weak repulsion from an external magnetic field. Diamagnetic materials are found in nature and are used for a variety of applications, such as shielding and cooling. They are also used in everyday life, such as in MRI machines and magnetic jewelry.
