[nanoRequest] Formula for shielding the field from a permanent magnet

I'm working on a formula for shielding the field from a permanent magnet. The formula calls for silver coated magnetic (iron oxide) microspheres having particle sizes of 5 to 75 microns in diameter with a mean particle size of about 45 microns, and typical silver thickness of 500 angstroms. It does not indicate whether to use solid or hollow microspheres however.

I would like to purchase a small quantity (1 ml.) of solid and/or hollow silver coated magnetic (loose with no binders) microspheres for experimental purposes. I'm working on a toy design on my own budget so cost is a concern until a prototype is developed after which, with investors involved, I'll be in a position to purchase larger quantities.

Can you supply these silver coated magnetic microspheres or will you please refer me to a supplier/manufacturer who does the silver coating?

The figures stated above are approximate; so, if you have anything in production close to these figures, it may be best to try them for the initial experiments.