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General Science => General Science => Topic started by: andyfresle on 13/07/2004 21:23:05

Title: Is it possible to interfere with a permanent magne
Post by: andyfresle on 13/07/2004 21:23:05: Is it possible to interfere with a permanent magnet with any material. metal, anything other than Electricity??
Title: Re: Is it possible to interfere with a permanent magne
Post by: tweener on 14/07/2004 22:40:04: What do you mean by interfere? You can change the pattern of the field with pieces of ferrous metal or other permanent magnets, but not really change the magnet itself. If you use another permanent magnet to apply a reverse field for a long time, or heat the first one, you can partially de-magnetize it.

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John - The Eternal Pessimist.
Title: Re: Is it possible to interfere with a permanent magne
Post by: andyfresle on 15/07/2004 08:24:14: quote:
Originally posted by andyfresle

Is it possible to interfere with a permanent magnet with any material. metal, anything other than Electricity??

By this I mean interfere with the magnetic flux ie block the magnetic fiels wirh no damage to the magnet and fast. I want to use a material like a switch. placed in between to turn off the field, remove to turn on
Title: Re: Is it possible to interfere with a permanent magne
Post by: gsmollin on 15/07/2004 17:02:11: Yes, a ferromagnetic material can be placed in the magnetic field, and used as a shield. The high permeability of the shield will confine the field, and route it around the area you wish to shield. Note that for maximum effectiveness, the shield must be closed- either around the magnet, or around the volume you wish to shield. The best magnetic materials are rather expensive- mu-metal, or permalloy. Ordinary transformer grade silicon steel is also effective at low cost. For the cheapest shield, use low carbon steel.