|MadSci Network: Physics|
Hi Chun Ming, This is an interesting question, and one that metallurgist and physicists are still discovering answers for. It is the electrons in a localized region called a domain that must interact for a material to become magnetic. When the interaction of the electrons with a magnetic field results in a lowered energy state, the material can retain a magnetic field. Anything that changes the relative positions of the electrons in a crystaline structure will affect how they interact and their ability to become magnetized. The different elements that are added to iron change its crystaline structure, and thus its ability to be magnetized. Additionally, not all crystaline forms of iron are magnetic. The face centered cubic structure of iron is not magnetic. The interaction of the electrons in a face centered cubic iron structure does not result in a lowered energy state when it interacts with a magnetic field. This is a simplified answer to a complex materials characterization question. In summary, it is the interaction of the electrons in a domain, and not any single pair of electrons, which determines how magnetic any given alloy system will be. Bob Novak Specialist -Process R&D Carpenter Technology
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