Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: ScientificSorcerer on 07/04/2015 13:35:20

Title: Are a lot of small superconductors better then one big one?
Post by: ScientificSorcerer on 07/04/2015 13:35:20

If you know anything about superconductors then you would know that it's only skin deep, the so called penetration depth is were most of the quantum action happens.

This is what I want to know, are a lot of thin layered superconductors better then just one big superconductor in terms of Meissener effect levitation strength? 

lets say I make one large superconductor disk about an inch in diameter which is an inch thick.

next I make 4 other superconductor disks which are 1 inch in diameter and  1/4 of an inch thick each.  I layer the 4 thin superconductors on top of each other...

If I pour liquid N2 on the samples and levitated magnets with weights on them which would hold more weight?

Title: Re: Are a lot of small superconductors better then one big one?
Post by: evan_au on 09/04/2015 12:46:45

I have never tried the experiment, but I would guess that the bottom disk would shield the upper disks, to a large extent.
However, if you laid the 4 superconductor disks side-by-side, I expect that they would support more mass, because there is no shielding effect.

There is another area where you want many small superconductors, and that is in superconducting wire (http://en.wikipedia.org/wiki/Superconducting_wire).
The many fine wires provide more surface area, and more immunity to changing magnetic fields.