is there any material that blocks magnetic feilds?
Depends on how strong the field is, most materials, if of sufficient thickness, will block a magnetic field.
There are many things that block magnetic fields but it mainly depends on the kind of material we take. If the metal or material that we take itself is a diamagnetic substance then it will oppose the magnetic fields to which it is exposed. In case of normal ferro magnetic substances or in other normal substances the lowering of temperature and at the superconducting temperature or transition temperature all metals or materials will oppose or block magnetic field and act as complete enemies of magnetic fields. Usually all metals and magnetically attractive substances will block the magnetic fields to penetrate them at the transition temperature.
While Mu-metal is one of the best, especially for static or low frequency magnetic fields, ordinary steel or iron will have some effect and may be cheaper and easier to get.
