Diamagnetism

Definition

Diamagnetism is a type of magnetism that occurs in materials that do not have any unpaired electrons, causing them to be repelled by magnetic fields. This property arises because the induced magnetic field in these materials is opposite to the applied magnetic field, leading to a very weak form of magnetism. Diamagnetic materials can be easily identified as they are pushed away from magnets, unlike ferromagnetic or paramagnetic substances.

5 Must Know Facts For Your Next Test

1. Diamagnetic materials include substances like copper, bismuth, and graphite, which show very weak repulsion when placed in a magnetic field.
2. The effect of diamagnetism is typically very weak compared to paramagnetism and ferromagnetism, often making it difficult to detect without sensitive instruments.
3. When a diamagnetic material is placed between the poles of a strong magnet, it will move toward the region of weaker magnetic field strength.
4. The presence of an external magnetic field induces a small change in the orbital motion of electrons in diamagnetic materials, creating a magnetic moment that opposes the applied field.
5. The phenomenon of levitating frogs in a strong magnetic field demonstrates the effects of diamagnetism as it allows these small organisms to be suspended in mid-air.

Review Questions

• How does the presence of unpaired electrons influence the magnetic properties of materials such as diamagnets?
  • Diamagnets are characterized by having no unpaired electrons, which leads to their unique magnetic behavior. In contrast to paramagnetic materials that exhibit attraction due to unpaired electrons aligning with an external magnetic field, diamagnets generate a very weak repulsive force. The absence of unpaired electrons means that there is no permanent magnetic moment in diamagnetic materials, resulting in their behavior that opposes applied magnetic fields.
• Compare and contrast the behavior of diamagnetic materials with paramagnetic and ferromagnetic materials in response to an external magnetic field.
  • Diamagnetic materials exhibit a weak repulsion when exposed to an external magnetic field due to induced currents opposing the applied field. In contrast, paramagnetic materials are attracted to the magnetic field because they have unpaired electrons that align with the field. Ferromagnetic materials show strong attraction and can retain their magnetization even after the external field is removed. While diamagnets will always respond with repulsion, paramagnets and ferromagnets demonstrate varying degrees of attraction based on their electron configurations.
• Evaluate the implications of diamagnetism in practical applications and how it differs from other forms of magnetism in engineering technologies.
  • Diamagnetism has unique implications in various engineering applications such as magnetic levitation systems and sensitive measuring instruments. Unlike ferromagnetism, which can lead to permanent magnets and is utilized in motors and transformers, diamagnetism is exploited for its ability to provide non-contact support, as seen in maglev trains or superconductors. Understanding diamagnetism's effects allows engineers to design systems that leverage its unique properties for innovative solutions while considering safety and efficiency that differ from traditional ferromagnetic technologies.

Related terms

Paramagnetism: Paramagnetism is the form of magnetism exhibited by materials that have unpaired electrons, which align with an external magnetic field, resulting in a weak attraction.

Ferromagnetism: Ferromagnetism is a strong form of magnetism found in materials like iron, where the magnetic moments of atoms align parallel to each other even in the absence of an external magnetic field.

Magnetic Susceptibility: Magnetic susceptibility is a measure of how much a material will become magnetized in an external magnetic field, with diamagnetic materials having a negative susceptibility.