Superconductive nonmagnetic material levitation

[elementcollector1]

Alright, I feel stupid for posting this, because I have the distinct feeling this will be shot down in a matter of a few posts. But I was discussing a superconducting project with a friend, and also talking about alternative levitation ideas (namely, http://www.youtube.com/watch?v=A1vyB-O5i6E). She asked me why I didn't combine the two, as this would allow me to theoretically levitate anything with a superconducting electromagnet.

From my understanding, superconductors have zero electrical resistance when active. So, a superconducting magnet is able to exhibit a current without any applied voltage. The magnetic field used to levitate the frog was 10 Tesla, but I don't have the proper understanding of the math to calculate the appropriate corresponding strength of a superconducting electromagnet.

 

Now, let's say I did build one of these superconducting electromagnets, and it was strong enough to levitate a frog or two. Could it exhibit the Meissner effect and 'lock' the object in two dimensions, or is that specific to magnets only? I'd say it's specific to the magnets, but I would also say frogs can't levitate...

[Enthalpy]

Elements of answers in bulk:

 

Type I superconductors, the less capable ones, have zero resistance if low enough below the transition temperature, in a field small enough, with a current density small enough. These exhibit the full Meissner effect.

 

For significant induction, only type II superconductors accept the necessary current density and field, and these do have a resistance, though much smaller than metals at normal temperature. These are used at colliders and so on, because there's no choice. They demand helium cooling for any interesting induction.

 

The coil that levitated the frog in Holland was resistive, if I remember properly. Put a few tens of MW in copper, cool with water consequently, get 10+ tesla.

 

Unfortunately, building and powering such a coil is difficult - I'd say too difficult for your present knowledge. A superconducting coil is too difficult as well.

 

The frog levitated due to diamagnetism, especially of its water. It also works with pyrolytic carbon, among the common substances. This is not the Meissner effect. Stability results from the shape of the field and of the weight (otherwise the stable position would be simply: far from the magnet): the induction must be stronger at the sides and at lower positions, which is often the case, say at a ring (flat annular) coil.

http://en.wikipedia.org/wiki/Diamagnetism

resistive coils, superconducting coils and permanent magnets behave in a similar way for that.

 

The effect of the object on the magnetic energy is locally like 0.5*B²/µ₀*X, but the field rearranges a bit, so the net coefficient is <0.5, not by a magnitude. If this energy varies with the height faster than the gravitation energy does, the object levitates.

 

What is accessible to simple experiments is:

- curve the surface of water by a strong permanent magnet

- levitate pyrolytic carbon on permanent magnets

- more ?

[elementcollector1]

Ah well - it was worth a shot...

I guess I'll have to stick with neodymium magnets until some better technology comes along, then.