Magnetic reluctance

[sbkenn]

Hi all. I haven't been able to find a thread that this fits in so:
What material has the highest reluctance to magnetic fields ? Is air the best there is, or otherwise ?
Another question that does, I think, belong here: In a PMA, can anyone confirm that alternating radially polarised magnets, with a gap between them (6 x 24degree pairs.. 6 degrees air gap) is better than circumferentially polarised ?

Thanks

 

[FPelec]

Theoretically, diamagnetic materials (e.g. pyrolytic carbon) have a lower magnetic permeability if compared to vacuum (or air). However this has little, if any, practical engineering applications, since the difference is extemelly small.

Si duri puer ingeni videtur,
preconem facias vel architectum.

 

[sbkenn]

Thanks and the "extremely small" is pretty much what I expected.