Subject: Can magnetism be a substitute for chemical reactions?

I heard of several materials that are canidates for magnets and lose 
little or no current in doing so.  I later wondered if switching the 
magnetism of a superconductive magnet on and off in a closed circuit 
instead of a chemical blast could be used to power something.  Just like a 
car engine, instead of adding fuel to a car, why not control magnetism to 
push on the piston just like a chemical explosion does on a typical car.  

Re: Can magnetism be a substitute for chemical reactions?