Diamagnetic substances are those which develop feeble magnetization in the opposite direction of the magnetizing field. Such substances are feebly repelied by magnets and tend to move from stronger to weaker parts of a magnetic field.
Properties of diamagnetic substances:
Diamagnetic substances are those in which the net magnetic moment of atoms is zero.
- The susceptibility has a low negative value. (For example, for bismuth χm= ? 0.00017).
- Susceptibility is independent of temperature.
- The relative permeability is slightly less than one.
- When placed in a non uniform magnetic field they have a tendency to move away from the field. (i.e.) from the stronger part to the weaker part of the field. They get magnetized in a direction opposite to the field as shown in the Fig..
- When suspended freely in a uniform magnetic field, they set themselves perpendicular to the direction of the magnetic field (Fig.). Examples : Bi, Sb, Cu, Au, Hg, H2O, H2 etc