What is Ferromagnetism?

Certain materials are attracted to magnets, while others exhibit little to no interaction. Those that are attracted are described as having ferromagnetic properties. The most common ferromagnetic materials include iron, nickel, and cobalt. These materials possess a degree of permeability, allowing them to respond to an external magnetic field. They also exhibit a level of magnetic coercivity, which enables their atoms to become magnetically aligned when influenced by a strong external magnetic field. Once the external field is removed, the remanence of the magnetized material may enable it to remain magnetized indefinitely.

Magnetic fields affect ferromagnetic materials by aligning the crystalline structures within their molecules. A material’s coercivity determines the extent of this alignment; higher coercivity leads to a more intense and aligned state, resulting in a stronger magnetic field. For instance, a steel screwdriver tip can be magnetized by sliding a magnet along it in one direction. This process alters the molecular structure of the tip, allowing it to attract and hold metal screws. However, the induced magnetic field in ferromagnetic materials can be permanently damaged or significantly weakened under extreme conditions. Heating a ferromagnetic material beyond a specific temperature or subjecting it to consistent physical impacts can cause its crystalline structures to become misaligned, resulting in a loss of its magnetic properties.