Diamagnetised

Diamagnetised refers to a state or property of a material when it is subjected to an external magnetic field. In this state, the material exhibits a magnetic moment that is antiparallel to the applied field. This means that the material is repelled by the magnetic field, rather than attracted to it. Diamagnetism is a fundamental property of all materials, but it is often masked by stronger magnetic effects such as paramagnetism or ferromagnetism when they are present.

The diamagnetic effect arises from the orbital motion of electrons within the atoms of the material. When an external magnetic field is applied, it induces a change in the orbital motion of these electrons. According to Lenz's Law, this induced change creates a magnetic field within the material that opposes the applied field. This opposition results in a net repulsion of the material from the external magnetic field. The strength of the diamagnetic effect is typically weak and independent of temperature.

Materials that are strongly diamagnetic are very rare. The most common examples include superconductors, which expel magnetic fields completely (the Meissner effect), and materials like bismuth, graphite, and pyrolytic carbon. While all substances exhibit diamagnetism, it is usually overshadowed by other, more potent magnetic properties like paramagnetism (weak attraction) and ferromagnetism (strong attraction). Therefore, a substance is often described as diamagnetised only when diamagnetism is its dominant magnetic characteristic.