Is there any material that blocks a static magnetic field? So that if I put it between a magnet and a piece of metal, they won't interact with each other?
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$\begingroup$ Mu-metal is designed to be used as a magnetic shield. "Mu-metal is a nickel–iron soft magnetic alloy with very high permeability". One of the things I've used it for is protecting phototubes used near magnets in physics experiments. The field screws up the tube's electron trajectory otherwise. $\endgroup$– BobTMay 19, 2017 at 17:02
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$\begingroup$ BobT thanks, interesting, is there any attraction or repulsion of this as you move it close to a magnet? $\endgroup$– ergonMay 19, 2017 at 19:43
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$\begingroup$ I would assume that it is attracted like any other ferrous metal. I don't actually remember whether it was or not when I used it- the tube assemblies were pretty well tied down. $\endgroup$– BobTMay 19, 2017 at 23:25
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2 Answers
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Yes, there are several different ways to manipulate magnetic fields. One way to shield an area from a magnetic field is to place a highly ferrous material like iron next to the source of the magnetic field. The iron will absorb the field in such a way that the magnetic field would be much smaller on the other side of the iron material.
Notice how in this simulation the iron sheet is absorbing the field and barely letting anything through. This website goes into deeper detail on how materials absorb magnetic flux.
Superconductors can be used for magnetic field shielding as well. Superconductors repel magnetic fields much more efficiently than say steel but is much more expensive.
In this picture you can see that the magnetic field lines are repelled from the sheet of superconducting material. If you would like to learn more about superconducting shielding take a gander at this website.
It is also important to note that while both these cases will keep two magnets from interacting with each other that does not guarantee that they will not interact with the shield itself. In the case of an iron based shield magnets will be attracted to the shield and in the case of a superconducting shield it will be repelled.
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$\begingroup$ Drew_J very interesting, thanks, so there is no shield that will not interact with the magnets? Also, the level of interaction will be as strong as between the magnets, or less/more? $\endgroup$– ergonMay 19, 2017 at 20:01
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$\begingroup$ @ergon I am not aware of a material that absorbs magnetic fields without interacting with the magnet. At some point the field has to be absorbed or reflected. Iron absorbs and superconductors reflect. $\endgroup$– Drew_JMay 19, 2017 at 20:18
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Yeah, you can use what is known as a Faraday cage or Faraday shield, which is an enclousure of iron used to block electromagnetic fields.
