Diamagnetism is a fundamental and weak form of magnetism found in all materials, though often masked by stronger magnetic effects like paramagnetism or ferromagnetism. It causes materials to exhibit a very slight repulsion when placed in an external magnetic field.
Diamagnetism arises from the orbital motion of electrons around the nucleus. When an external magnetic field is applied, it slightly alters these orbits, creating tiny induced magnetic fields that oppose the applied field, according to Lenz’s Law. Since this response is always in the opposite direction, diamagnetism is inherently negative in magnetic susceptibility.
Key features of diamagnetism:
- It is temperature-independent.
- It exists in all materials, but is usually only noticeable when no other magnetic effects are present.
- Strong diamagnets include materials like bismuth, graphite, and superconductors, which can even levitate in strong magnetic fields due to perfect diamagnetic behavior.
Diamagnetism is important in precision instruments, magnetic levitation experiments, and the development of advanced materials like superconductors. While subtle, it reflects the fundamental quantum nature of how materials interact with magnetic fields.