What physical property is described by the term 'residual magnetism'?

Residual magnetism refers to the magnetization that remains in a material after an external magnetic field is removed or after the material has been demagnetized. This property is particularly important in ferromagnetic materials, which can maintain a certain level of magnetism even when not subjected to a magnetic field. This characteristic can lead to a range of applications and implications in magnetic storage, sensors, and electric motors.

For instance, in magnetic storage devices, residual magnetism is harnessed to retain information. In other contexts, it can cause problems, such as unwanted magnetism in components that must be demagnetized for precision applications. Understanding residual magnetism is crucial for technicians working with magnetic materials and devices, as it affects their performance and functionality.