I need clarifications on Meissner effect. 1. According to this theory, when any diamagnetic substance is cooled below its critical temperature, it becomes a superconductor and it expels magnetic flux from inside. Is it applicable only to a diamagnetic substance or ferromagnetic substances like iron also? 2. Expulsion of magnetic field means 'removal of the mag flux from inside the material to the outside'. Here a point which I could not understand is that since the permeability of a diamagnetic substance is almost negligible, already no magnetic flux could have penetrated into it. Then what does it mean that it 'expels' the magnetic flux present inside it? 3. Can a 'magnetic levitation experiment' be conducted by placing a magnet on a super-cooled ferromagnetic material such as iron or steel?