Jälkimagneettisia

Jälkimagneettisia refers to residual magnetism that remains in a ferromagnetic material after the external magnetic field that caused the magnetization has been removed. This phenomenon is a fundamental property of ferromagnetic substances, meaning they retain a degree of magnetization even without an applied field. The strength and persistence of this residual magnetism depend on the material's magnetic properties, such as its coercivity and remanence.

Materials with high coercivity, like hard magnetic materials, are designed to retain a significant amount of magnetization, making them suitable for permanent magnets. Conversely, materials with low coercivity, such as soft magnetic materials, lose most of their residual magnetism when the external field is removed, which is advantageous for applications like transformer cores where rapid changes in magnetization are required.

The process of demagnetization aims to reduce or eliminate jälkimagneettisia. This can be achieved by applying an opposing magnetic field or by heating the material above its Curie temperature, the point at which it loses its ferromagnetic properties. Understanding and controlling jälkimagneettisia is crucial in various technological fields, including data storage (e.g., hard drives), magnetic shielding, and the design of electrical machinery. The presence of residual magnetism can influence the performance and behavior of magnetic devices.