[femm] Materials....

["Scott Norton" <scott_norton@xxxxxxxxxxxx>]

Like others, let me first claim my ignorance about magnetics...
(Why do the equations have to seem so much more complicated than
electrostatics!?!?)

My mission: To increase the B field gradient in a very small
localized volume. I have a couple nice fairly large magnets and I 
want to introduce some strips of metal material around my small volume
to
cause large field gradients. I'd like to explore my options 
using FEMM. 

First of all, what type of material am I looking for that enhances
magnetic field gradients? What's the material specification that tells
one
this? For instance, I've seen nickel strips introduced into a uniform
magnetic field that was used to create gradients. Why was
it chosen? What's better? If I was to model nickel in FEMM, do I need
the BH curves or is magnetic permeability enough?

Any information would be really helpful! Thanks!
-Scott