magnetisierten

Magnetisiert (German for magnetized) describes a material that has acquired a net magnetic moment as a result of exposure to an external magnetic field or current. In magnetized states, the vector M, the material’s magnetization, represents the magnetic moment per unit volume; it relates to the magnetic flux density B and the magnetic field H by B = μ0(H + M) in SI units.

The underlying mechanism involves magnetic domains, regions where microscopic moments align. In many materials—ferromagnets and ferrimagnets—domain walls shift under an applied field, and, as the field increases, moments align until saturation. Temperature matters: above the Curie temperature the orderly magnetization fades, returning the material to a paramagnetic state.

Magnetization can be permanent or temporary. Hard magnets exhibit high coercivity and remanence, retaining magnetization after the external field is removed; soft magnets are easily demagnetized and are used where variable magnetization is needed. Methods to magnetize include applying strong static or pulsed fields, mechanical processing, or magnetic annealing (heat treatment in a magnetic field).

The magnetic state is described by hysteresis curves, saturation magnetization, coercivity, and remanent magnetization. Common units are A/m for magnetization M and tesla for magnetic flux density B.

Applications range from electric motors, generators, and transformers to magnetic sensors, data storage, and biomedical imaging. Factors such as temperature, aging, and exposure to opposing fields can cause demagnetization, affecting performance.