Superconductor levitation above a magnetic track

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wapiti
Posts: 1
Joined: Fri Nov 14, 2008 2:48 pm

Superconductor levitation above a magnetic track

Postby wapiti » Fri Nov 14, 2008 2:50 pm

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 http://www.youtube.com/watch?v=1zwBoBbHR4I

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

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

Thanks for your time, any links and information are much appreciated!

aditi405
Posts: 31
Joined: Fri Jul 25, 2008 3:05 am

Re: Superconductor levitation above a magnetic track

Postby aditi405 » Sat Nov 15, 2008 7:58 am

Hi Wapiti,
Hope this helps you
wapiti wrote:So . . . If I do not purchase a special enhanced flux pinning superconductor will my project still work as shown in the video?

Since you are following instructions it would make sense to do as specified. it is possible that enhanced flux pinning superconductors were used in the experiment so that the levitation is more stable, if i can say so. (so that minor physical disturbances do not affect the levitation too much). So it would make more sense to buy a 0.5" enhanced flux pinning YBCO pellet than a normal 1" one. maybe u cud use an overhead projector so that the levitation would be visible to your audience.
wapiti wrote:My understanding is the Bismuth based superconductors will levitate longer than the Yitrium based superconductor when cooled?

That is true. Critical temperature (Tc) for Bi based superconductors is more than for YBCO, so once you remove liquid nitrogen (after cooling ) Bi based superconductors will levitate longer than YBCO. but in the presence of liquid nitrogen there wont be a difference because 90K which is the temperature liquid nitrogen provides, is lower than the Tc of both Bi and Y superconductors.

many graduate students would have more access to their labs. maybe you could ask one such graduate student in the condensed matter physics department at ur college (unless ur in high school ) to help you out with finding materials at cheaper rates or maybe they would even let you borrow magnets and stuff for a few days. But that is provided you have good contacts with some of them. All the best!




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