magnetic insulator

Not completely. Your composite will shield against low frequency fields (I use 100 kHz as the upper limit, but some people use 250 kHz - it's a judgement call). Even at low frequencies, the effectiveness of the shielding depends on the thickness and the care used in construction.

So how we can build a completely shield against all magnetic fields ? What is the best composite ??? http://www.nature.com/nature/journal/v423/n6935/abs/nature01617.html Are you recommended this for my composite ?

Maybe with a superconductor. You need to cool with liquid nitrogen. Probably not what you're looking for.

http://www.nature.com/nature/journal/v423/n6935/abs/nature01617.html What is this dear friend ? Are you recommended this for my composite?

You cannot build a complete shield. You can shield 90% or 95% or 99% or 99.9% or 99.999%, but never 100%.

You just have to specify the field strength, the frequency and the desired reduction.

I have a NdFeB magnet i take a picture from it : Inner packing dimensions: 100 x 100 x 50mm Outer packing dimensions: 200 x 200 x 200mm Do you want mor info?

Yes. Will this magnet besitting still or moving? What is it's magnetic strength at, say, 20 cm? What do you need to reduce that to?

-the magnet moving -magnet length is 10 cm -i want to have a magnet with one pole (however the one pole magnets is IMPOSSIBLE ; so we must use insulators on the poles ... ) OK?

You cannot insulate one pole of a magnet. Where would the lines go? What are you trying to do?

What is your thought about MetGlas ? (his permeability is +1,000,000 ) http://www.lessemf.com/mag-shld.html#278 what composite you recommended ?

Magnetic field lines circulate from one end of a magnet and return to the other end of the same magnet. You can use high permeability material to conduct most of the field in a specific path but it must eventually return to the magnet. The more complex and long the path is the more leakage you will get through the air. The pesky magnetic line only want to return to their home at all cost. you can try to drive them somewere else but you cannot prevent them to return home. Unless you want to bend the laws of nature, you will have to adapt your application.

Can this work really? http://i30.tinypic.com/208bqqx.jpg

No. Really. Even though you can something that is a LITTLE BIT like that, you still have both poles unshielded. If you don't believe people who know how magnetic lines go, download Quickfield (The student version is free and it will do what you want) and do an FEA simulation on the dadburn thing. Really.

I asked it from lessemf.com and he say that it is possible !

Then ask him how.

yes this can be done what you do not see is the magnet on the mumetal to caounteract the feilds i see you are looking at a overunity motor just by the drawing

they have a unit running in austrailia problem is the cost of the mumetal parts was to high and it also needs to be hardened or it will crack and break if there is any vibration at all mumetal is a pain in the ass to work with at the best of times.

if you are not worried about a feild on the inside use 2 magnets and a steel ring make sure you use the right glue as well or they will come flying out locktite has a good one we have used $600 per gallion also watch the aluminum as well for some reason there is a problem with some aloys and static build up as it rotates.

I must've been asleep at the wheel, since forever, because when I first was taught electrical theory back in the 60s I learned that you could not insulate a magnetic field, only redirect the lines of flux. Maybe that is what is being asked here; what material will redirect all lines of flux away from what is wanted to be shielded. OK, go ahead and beat me up, I can take it.

permeabilities of air is 1 permeabilities of MagnetShield is 4000 so He say that the lines want to travel from MagnetShield ! OK?

lessemf.com say that You are correct. You can only redirect the magnetic field lines. The lines drawn on your diagram are approximately correct. Note that shield size and thickness is relevant.