| MadSci Network: Physics |
This is way too big a question to answer here. You need to get a
good book on magnetism. One such is "Introduction to Magnetic Materials"
by Cullity published by Addison Wesley 1n 1972. The URL below will get
you started on the modern stuff.
http://
www.research.ibm.com/resources/news/20010518_pixie_dust.shtml
Try the links in the MadSci Library for more information on Physics.