Having just conducted a experiment in which I levitated a small neodymium magnet above a liquid nitrogen cooled YCBO superconductor, I was wondering if anyone knew of any factors that affect the height at which the magnet levitates at (e.g does magnet strength affect it?), and whether this applies inversely (i.e does a stronger magnet allow a superconductor to levitate higher above it?). In addition, I was wondering whether anyone could think up an inexpensive (under £100, ($~170)) way to keep liquid nitrogen above the superconductor, which is 1" in diameter, in order that it remains at its critical temperature. I had thought of a half ping-pong ball and have yet to try that out - however, there is little insulation provided by that, so it would only work for a short while.

Sorry for the long post...

Any ideas would be very welcome.

"an inexpensive (under £100, ($~170)) way to keep liquid nitrogen above the superconductor"

 

What do you mean here? Do you want to float it above?

Edited January 16, 201214 yr by Tres Juicy

no, i want a way to keep the superconductor cold - i.e., hold the liquid nitrogen above it (in a cup attached? i don't know...) without using a sapphire crystal wafer to insulate it

How long do you want to keep it cool for, a few mins, hours, days?

 

We use trays similar to this:

 

http://www.wondermagnet.com/superconductor.html

 

But with a raised up area for the superconductor to rest on.

i used a tray like that in my demo a few days ago - but this time i want the superconductor to be floating on top of a very large magnet, not levitating a small neodymium magnet above it! This means that the superconductor will be out of the liquid nitrogen and so i need to find some way of making it so i can have liquid nitrogen near it (or on it), or just a way of insulating it so that having cooled it, it stays could for ~1 minute

What about putting it inside a bag and having it wrapped around the magnet?

having the bag wrapped around the superconductor and filled with liquid nitrogen? could work, i just wonder whether there is a plastic bag that wouldn't become brittle and break...

having the bag wrapped around the superconductor and filled with liquid nitrogen? could work, i just wonder whether there is a plastic bag that wouldn't become brittle and break...

 

That was my concern, but I thought it would be worth a go...

to get back to the main point (cos i have a decentish idea for insulation now, though more would be appreciated), does anyone know whether the strength of the magnet used is proportional to the height that the superconductor levitates at? cos if so, then I'm gonna go ahead and spend £75 on a 26kg force magnet