Further investigation was put into the idea of increasing the spacing between magnets as a way of creating a more effective shielding effect. The space was increased from 5.6cm to 9.8cm to observe the effect:
As predicted, there is less of an attraction between the shield and magnet at a greater distance. However, this drop in field strength closely mimics that of the separated, unshielded magnets. This suggests that the reduced potential between the shield and magnet is mainly down to the way the magnetic field strength falls away with distance, rather than a better shielding effect; again, the potential energy between the shield and the magnet is not much less than when both magnets are exposed.
From results obtained at Magnetic Shields Ltd., it can be said that a magnetic shield is still not a suitable method of completely shielding one pole of a magnet from the other. It also stands that magnetic monopoles are non-existent, and that shielding is again not a solution. Despite such limitations, the useful role of MuMetal® shielding for applications in which field distortion or confinement is necessary cannot be stressed enough. Figure 4 in the post Magnetic Shielding depicts some typical shielding factors obtained by smaller shields containing strong magnets, whilst some larger shields that contain weaker fields reach factors many times this magnitude.
