What Is a Magnetic Wall?
Ordinary magnets are composed of ferromagnetic materials, with ferromagnetism referring to the property of an object being attracted to a magnet.
Ferromagnetic materials consist of atomic layers of magnets, each possessing a vector quantity known as a magnetic moment, which indicates the strength of the magnetic force.
Aligned regions of the magnetic moment are termed magnetic domains. The boundary layer between magnetic domains in different directions is known as the magnetic wall.
Uses of Magnetic Walls
Magnetic domains and walls are crucial in analyzing the behavior of ferromagnetic and ferrimagnetic materials and for practical applications.
Common uses include the magnetic strip on the back of a credit card, PC hard disks, and the backs of train or bus tickets and commuter passes. These are coated with ferromagnetic material, recording information on the magnetic walls (magnetic domains) as artificial digital data of 0s and 1s, facilitating data exchange between these media and integrated systems.
Principle of Magnetic Walls
A simple example to understand the principle of magnetic walls involves metal needles and clips.
A new metal needle or clip, initially non-magnetic, can exhibit magnetic properties when rubbed with a magnet, attracting each other.
This is due to the change in the distribution of magnetic domains and walls within the needle or clip upon contact with a magnet. Rubbing alters these domains, leading to a state where magnetic poles remain on the needle or clip’s surface, effectively turning them into magnets.
Items like credit cards with magnetic strips should be kept away from magnets to avoid irreversible changes to the magnetic domains and walls.
The concept of magnetic walls is also essential in analyzing new ferromagnetic materials and products, such as ferrites.