Magnetic fields such as a field from a neodymium magnet?

[Chemics]

Is there a material that blocks or reflects magnetic fields such as a field from a neodymium magnet?

 

[Vanadium 50]

No. The best you can do is to move the field lines away from one area and towards another.

 

[LURCH]

Right; magnetic shielding is usualy done with iron, which doesn't really "shield" in the conventional sense. Instead, it causes the magnetic field to concetrate where the iron is, thus greatly weakening the field strength beyond that bit of iron.

 

[Dale]

Is there a material that blocks or reflects magnetic fields such as a field from a neodymium magnet?

Iron or mu metal (sp?)

 

[Vanadium 50]

It is spelled "mu metal", but it doesn't block or reflect. All it can do is move field lines from one place to another, like Lurch describes.

 

[Gokul43201]

Is there a material that blocks or reflects magnetic fields such as a field from a neodymium magnet?

Do you have a specific problem that you wish to apply this to?

 

[Dale]

In the construction of passively shielded MRI suites we call it a shielding material. On one side of the shielding you may have a field of several tesla and on the other side a field of several nanotesla. So to me it seems fair to call that "blocking" the field.

Obviously reflecting is the wrong word, since that refers to a wave behavior. But to me "blocking" seems close enough to "shielding".

 

[TVP45]

In the construction of passively shielded MRI suites we call it a shielding material. On one side of the shielding you may have a field of several tesla and on the other side a field of several nanotesla. So to me it seems fair to call that "blocking" the field.

Obviously reflecting is the wrong word, since that refers to a wave behavior. But to me "blocking" seems close enough to "shielding".

Are you saying you've been able to knock an MRI down to nT with mu metal? May I ask how?

 

[Dale]

I have never seen it done with mu metal (too expensive), only iron. But it is pretty simple. Put the MRI in the middle of the room, and then place several hundred tons of iron in the walls ceiling and floor. Outside the room the field is very small.

 

[Chemics]

I am wanting to use a neodynium magnet to make a traffic light change when i pass over the trigger in the road with my motorcycle but I figured if the magnet is too strong it has to be doing something to the motor or electrical circutry on the motorcycle. So I thought that I would try to shield it somehow using an iron or some kind of material to either block or reflect the magnetic fields. From what people are saying though it sounds like a good reflection or any at all is near impossible or too much work/money.

 

[Dale]

You shouldn't need any shielding for something like that. Try http://rsinventionlab.com/archives/126". It may do the job for $15 or so.

 

[Chemics]

You shouldn't need any shielding for something like that. Try http://rsinventionlab.com/archives/126". It may do the job for $15 or so.

Thanks! This helped a lot!