Hysteresisväli

Hysteresisväli, often translated as hysteresis gap or hysteresis width, is a concept primarily used in the context of magnetic materials. It refers to the difference in the magnetic field strength required to reach a certain level of magnetization when increasing the field compared to when decreasing the field.

When a ferromagnetic material is subjected to an external magnetic field, its magnetic domains align. As the field is increased, the material becomes more magnetized. However, when the external field is reduced, the magnetization does not decrease linearly. Instead, some level of magnetization persists even when the external field is reduced to zero. This residual magnetization is known as remanence.

To demagnetize the material completely, a reverse magnetic field must be applied. The strength of this reverse field needed to bring the magnetization back to zero is called coercivity. The hysteresisväli is closely related to coercivity and remanence, as it quantifies the range of magnetic field over which this lagging effect occurs.

Materials with a wide hysteresisväli are considered "hard" magnetic materials. They are difficult to magnetize and demagnetize, making them suitable for permanent magnets. Conversely, materials with a narrow hysteresisväli are "soft" magnetic materials. They are easily magnetized and demagnetized, which is advantageous for applications like transformer cores and inductors where the magnetic field needs to change rapidly. The shape and size of the hysteresis loop, which visually represents this phenomenon, are crucial for selecting the appropriate magnetic material for a given application.