Non Magnetizing Material

Not at the moment. All indications are that it wouldn't be possible, but one never knows what some materials scientist may come up with.

Mike

What about materials that are anti-magnetic, like Bismuth. Do they pick up a field. After all, they are repelled by the magnet, so magnatisim is at work, isn't it?

Al

You're basicall looking for a magnetic version of a high dielectric constant material, I gather. Ordinary materials have small diamagnetic or paramagnetic responses, but not enough to be useful ordinarily. Ferromagnetic materials have a large response to magnetic fields, but as you say, usually exhibit remanent magnetization when the external field is removed.

There are specially prepared magnetic materials, such as Permalloy, Super-Permalloy, and mu-metal, that have very high magnetic permeability with very low remanent magnetization. The bad news is that they tend to be very expensive, and their properties depend crucially on their microcrystalline structure, so that they lose many of their nice properties if you bend them, hammer them, or even machine them. They have to be carefully heat-treated after finishing.

Another possibility would be some sort of electromagnet gizmo based on negative feedback: if you attach a Hall effect magnetic field sensor to a coil, and servo the coil current to keep the field at zero, it will be strongly attracted to any magnet in the neighbourhood, but won't do anything otherwise.

Cheers,

Phil Hobbs

"Bret Cahill" news: snipped-for-privacy@i42g2000cwa.googlegroups.com...

What do you mean "not turning into a magnet"? If you mean the material does not have magnetic moment, that is impossible, magnetic moment will always be induced whatever material you are using. If you mean does not hold the magnetic moment when field is removed, a lot of options exist, paramagnetic, soft ferromagnetic, superparamagnetic...