# Superconductor levitating above a magnetic track?

1. Nov 14, 2008

### wapiti

I have a science fair coming up for school, and while I have been doing a ton of research, I have a few questions. I am attempting to recreate an experiment in which a supercondcutor levitates back and forth along a track of permanent magnets. The track consists of 23 magnets, 3 magnets to a row, 7 magnets long, and 2 magnets laying perpendicular to the track. The experiment I am attempting to recreate is shown here at 3:52

The project even comes with very specific instructions shown here http://arxiv.org/PS_cache/arxiv/pdf/...803.3090v1.pdf [Broken]

The instructions specify that a (3 cm hexagonal) enhanced flux pinning YBCO superconductor was used. My problem is the store in which they purchased their superconductor has been discontinued.

Other websites and stores do sell enhanced flux pinning superconductors, but the largest diameter disk I have found is only .5" in diamter, and would be a bit too small for my audience. Anyone know of a website that sells enhanced flux pinning superconductors that are at least 1 inch in diamter? I have searched the Internet far and wide and I don't think such a store currently exists. So . . . If I do not purchase a special enhanced flux pinning superconductor will my project still work as shown in the video?

My options of "normal" superconductors that are not enhanced flux pinning are (1 inch daimeter) YBCO or Bismuth based superconductors available here http://www.users.qwest.net/~csconductor/.
My understanding is the Bismuth based superconductors will levitate longer than the Yitrium based superconductor when cooled?

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As a side note the instructions specified that magnets of 3" x 1/2" x 1/4" were used. The instructions claimed that these magnets are available for $4 each. The cheapest I have found these ND-FE-B grade N42 is for$8.50 each shown here http://www.kjmagnetics.com/products.asp?cat=11 Does anyone have a link or know of somewhere where I can purchase these magnets cheaper?

The school is providing \$250 towards the project, and the less I have to spend from my own pocket the better

Last edited by a moderator: May 3, 2017
2. Nov 14, 2008

### f95toli

When I was PhD student we had a "superconducting train" which consisted of a YBCO tables inside a styrofoam model of a train (with room for LN2) levitating on top of a magnetic strip (i.e. not a collection of bar magnets, but really a "track).
The track was in the shape of a loop and the "train" would go round and round for quite a while. We used this to demonstrate superconductivity to undergraduate students.

As far as I remember the YBCO tablet came from a standard Meissner kit, i.e. there was nothing special about it. Flux is primarily pinned in defects and impurities meaning a "bad" tablet will trap flux more easily than a "good" (uniform and defect free) tablet.
Hence, just about any piece of sintered YBCO will behave in more or less the same way (a real single crystal wouldn't work as well). I don't think you need an enhanced flux pinning material for something as simple as a train.

My advice would be to just buy some YBCO in the right shape. BSCO would also work but it is a more complicated material and I suspect it is more expensive, and it wouldn't levitate for longer than YBCO (the Tc of 2212 is higher than for YBCO, but that doesn't matter since the superconductor is immersed in LN2).

3. Nov 4, 2009

### jollyhawley

I am attempting to perform the same kind of project. I was wondering if you could tell me what you ended up doing and if you were successful, or if anyone else reading this has attempted this. Any information would be appreciated. Thank you.