What is the effect on temperature on permanent magnets?

sjr · Post by **sjr** » Wed Nov 08, 2006 3:09 pm

I am just starting to gather research on this topic. I would be grateful on any suggestions on where to start. I would also be interested if anyone had an opinion on how best to change the temperature of the magnet. Right now I am considering putting it in boiling water to heat it up, and in the freezer to make it cooler.

Thank you,
sjr

deleted-71588 · Post by **deleted-71588** » Wed Nov 08, 2006 4:17 pm

If you don't know what the Curie temperature is and what happens, try reading:
http://www.mceproducts.com/knowledge-ba ... .asp?id=23

You won't hurt the magnetic properties of a magnet by lowering the temperature; however, you may make it brittle or cause it to crack. For example, powdered Iron magnets that have gotten wet may have a fissure that retains water that when frozen will expand and crack the magnet.

Water in a heavy bottomed pan (or a lighter pan with a way of suspending the magnet so it isn't in contact with the pan) and a cooking thermeter is one way.

A baking pan in an oven with an oven thermometer is another and this avoids porous material, corrosion issues, and any splashes of hot water.

CAUTION: Adult supervision and burn precautions should be taken.

BEWARE: many magnetic materials have thermal memory of how long the material has been at a temperature the number of experiments a given magnet can be used for maybe limited unless you have a way of remagnitizing it.

Hope this helps in reducing the uncontrolled variables.

Searching for "Thermal properties of magnets" and including the material you are experimenting to further refine the search will give you other articles.

sjr · Post by **sjr** » Sun Nov 12, 2006 11:24 am

Thank you. Do you have any suggestions on a somewhat credible source that could give me an overview of magnets (for footnotes/bibliography)?

Louise · Post by **Louise** » Sun Nov 12, 2006 12:34 pm

sjr wrote:Thank you. Do you have any suggestions on a somewhat credible source that could give me an overview of magnets (for footnotes/bibliography)?

I would think this would be covered in a college level physics textbook or the encyclopedia, both of which you could probably find at your local library. If you go to the library and talk to the reference librarian, they can help you find specific reference materials.

Louise

deleted-71588 · Post by **deleted-71588** » Wed Nov 15, 2006 3:24 pm

If you are after translations of the primary historical papers on the Curie Temperature named after Pierre Curie, see the bibliograpy of: http://www.tribunes.com/tribune/art97/jos2e.htm and see what translations you can find in a college engineering or science library.

"Permanent Magnet Materials and their Application (Cambridge Studies in Magnetism) (Paperback) by Peter Campbell" is a relatively inexpensive reference book on modern permanent magnets. Other books in the same series may also be of interest.

There are lots of books on magnets and magnetic properties in general, but few of them deal with the effect you are researching.