Magnetic Domains - NDE

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Nondestructive Evaluation TechniquesNondestructive Evaluation EngineeringGlossaryPhysics of Nondestructive Evaluation > Magnetism > Magnetic Domains Magnetic Domains

After completing this section you will be able to do the following:

• Define a magnetic domain.
• Explain one way an object can be magnetized.

A magnetic domain is region in which the magnetic fields of atoms are grouped together and aligned. In the experiment below, the magnetic domains are indicated by the arrows in the metal material. You can think of magnetic domains as miniature magnets within a material. In an unmagnetized object, like the initial piece of metal in our experiment below, all the magnetic domains are pointing in different directions. When the metal becomes magnetized, which is what happens when it is rubbed with a strong magnet, all like magnetic poles line up and point in the same direction. The metal becomes a magnet. It would quickly become unmagnetized when its magnetic domains returned to a random order. The metal in our experiment is a soft ferromagnetic material, which means that it is easily magnetized but may not retain its magnetism very long. This can be done in real life with a paperclip.

Review:

1. A magnetic domain is region in which the magnetic fields of atoms are grouped together and aligned.
2. Ferromagnetic materials are easily magnetized but may not retain its magnetism very long.