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How does diamagnetism cause a material to be repelled by a magnet?

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Learn about magnetic fields and the levels of particles, atoms, crystals, and domains — magnet Magnetic fields and the levels of magnetism of particles, atoms, crystals, and domains.

Diamagnetism is a fundamental property of all matter, occurring when an external magnetic field is applied to a material. Contrary to the idea that only specific materials are affected, all substances exhibit diamagnetism, though it is often masked by stronger forms of magnetism like paramagnetism or ferromagnetism.12

The repulsion occurs because the external magnetic field alters the orbital motion of electrons within the material's atoms. According to Lenz’s law, this change in motion induces a circulating electric current that creates an internal magnetic field. Crucially, this induced field is directed in opposition to the applied external field.231

Because the induced magnetic moment always opposes the external field, the material experiences a repulsive force. This effect is characterized by a negative magnetic susceptibility, meaning the material is weakly repelled by magnets rather than attracted to them. This phenomenon is independent of temperature and is most observable in substances with symmetric electronic structures.123