The magnetic moments from atoms do not interact with each other at all. If an external magnetic field is applied, the magnetic moments are free to align with the field. If the moments interact to cause each other to align in the same direction, they are called ferromagnetic . Iron, cobalt and nickel are ferromagnets, as are the magnets on your refrigerator. If the moments interact to cause an alternating pattern such as in manganese, the material is said to be antiferromagnetic .
Some materials have different types of atoms with different moments, which interact.
These cause ferrimagnetic behavior, because some of the moments are canceled by other atoms, but some are not. Temperature, stress and impurities can all affect magnetic properties and play an important role in using these materials for engineering applications. All rights reserved.