Is it possible for something to reflect a magnetic field? For example if I use a large rare earth magnet if there something that will stop the field or reflect it all together?
Remember that magnetic shielding is not really “shielding” in the traditional sense. One cannot stop or block magnetic field lines. They will travel from the N pole of the source to the S pole. What we can do is to alter the path that these magnetic fields lines take on their journey.
All materials stop magnetic fields to a certain degree. The amount you need depends on the strength of the field. Brass is very good for stopping electromagnetic fields.
Some substances, which present diamagnetic properties, in special conditions (very low temperatures, near -273 Celsius) present this characteristic, they block magnetic field. But, if you want to have a room with no magnetic field in it, at normal conditions, there's another class of substances, with very high magnetic susceptibility and very low remanent magnetization, which drains the magnetic field through it, so, it can be used to build a room, for example. If the walls are made with this material (in practice, with some layers to be sure no flux will go out the wall), you can have a region with no magnetic field in it. One such material is Permalloy, with composition 78.5% Fe and 21.5% Ni, annealed at very high temperature (1100-1200 Celsius) to remove lattice defects.
