If I wanted a constant B field using an element

[Kidphysics]

Or some naturally occurring material what would I use. I'd like the strongest constant uniform magnetic field possible. Is there some sheet of material I can use?

 

[mfb]

Naturally occurring materials do not have strong or uniform magnetic fields. There are cheap, powerful, and uniform magnets available commercially, but they use special alloys and techniques to magnetize those elements.

 

[Kidphysics]

interesting, thanks; do you recommenced a place?

 

[mfb]

I don't want to recommend a specific manufacturer (and I don't know them anyway), search engines should give you a long list of them. Neodymium magnets are the most common type.