The property of a substance that possesses a
→ magnetic permeability
greater than that of a vacuum but significantly less than that exhibited by
→ ferromagnetism.
In the absence of an external magnetic field the atomic
→ magnetic moments of the substance
are randomly oriented and thus cancel each other out with no net total
magnetic moment.
Moreover the coupling between neighboring moments is weak.
However, when a magnetic field is applied magnetic moments align with the
direction of the
field and so the magnetic moments add together.
Therefore paramagnetic substances
affect external fields in a positive way, by attraction to the field
resulting in a local increase in the magnetic field.
The → magnetization vanishes when the field is removed.
See also: → para- + → magnetism
