Nonferromagnetic

Nonferromagnetic is a term in magnetism for materials that do not show ferromagnetism. Ferromagnets develop spontaneous magnetization due to parallel alignment of magnetic moments. Nonferromagnets do not exhibit this spontaneous order and typically respond weakly or only under an external magnetic field.

Diamagnetic materials develop magnetization opposite to an applied field. The effect is very weak, with a small, negative magnetic susceptibility. Diamagnetism is intrinsic and present in all materials to some extent, though it is often masked by stronger magnetic effects. Examples include copper, bismuth, and graphite.

Paramagnetic materials have unpaired electrons whose spins align with an external field, producing a positive susceptibility. The effect is modest and generally decreases with increasing temperature. When the field is removed, magnetization vanishes and there is little to no hysteresis.

Antiferromagnetic materials exhibit opposite alignment of neighboring moments, resulting in near-zero net magnetization below the Néel temperature. Their response to a field can be complex, with spin-flop transitions under strong fields. Despite internal order, they are considered nonferromagnetic because there is no parallel alignment that yields strong spontaneous magnetization.

Ferrimagnetic materials have unequal opposing sublattice moments and a net magnetization; they are magnetically ordered but are not ferromagnets in the strict sense. In practice, nonferromagnetic materials include diamagnets, paramagnets, and many antiferromagnets, which may be used when minimal magnetic interference is required.

Measurement of magnetic susceptibility and magnetization helps classify materials as diamagnetic, paramagnetic, or antiferromagnetic. Applications include electronic components and shielding where low magnetic response is desired.