Is the bar soft or hard magnetically? If hard is it pre-magnetized?
In rough terms all magnetic effects tail off as one over the cube of distance (holds for any dipole in an
inverse-square-law field, so as there aren't any magnetic monopoles, forces go with 1/r^3).
This means all magnetic phenomena are short-range (limited to a small number of multiples of the size
of the biggest magnet present)