Magnetilised

Magnetised is the condition of an object that has been endowed with a net magnetic moment, typically by exposure to an external magnetic field or electric current. In physics, magnetization is described by a vector field M, representing the magnetic moment per unit volume. When a material is magnetised, its magnetic domains—small regions with aligned moments—tend to align with the external field. If the alignment persists after the field is removed, the material is a permanent magnet; if it largely disappears, the material is a soft magnet or paramagnetic or diamagnetic depending on response.

Permanent magnetisation occurs in ferromagnetic or ferrimagnetic materials, such as iron, nickel, cobalt, and their alloys, due to interactions at the atomic level that produce high remanent magnetization. Induced magnetisation happens in most materials in the presence of a magnetic field, but may vanish when the field is removed. Soft magnetic materials are easily magnetised and demagnetised, making them useful in transformers and magnetic cores.

Methods to magnetise include exposing the material to a strong magnetic field, placing it inside an electromagnet, or passing high currents through coils. Demagnetisation can occur through heat, strong opposing fields, or mechanical shocks, and is influenced by coercivity and magnetic anisotropy.

Applications of magnetised objects include compasses, data storage, electric machines, magnetic separation, and medical imaging. The term magnetised follows British spelling; magnetized is the American variant.