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Lead zirconate titanate (PZT)  (Source: DIY Trade)
University research report observing high conductivity using surprisingly simple metal mix

By now, erroneous reports of "room temperature" superconductor have popped up frequently enough to make even the strongest optimist a bit skeptical.  Still, the steady advance of verified superconductors operating at higher temperatures has raised the hope of such a material eventually being found.

Now a team at the University of Bengal in India, led by Dhruba Dasgupta, has become the latest to cause a stir, reporting that they have observed what possibly appears to be superconductivity at 313 K.

The researchers used lead zirconium titanate (PZT) -- a common material used in capacitors and other electronics -- for the work.  They first cut a 2 cm × 2 mm piece of a commercial disks of the material.  They then stripped away the existing silver coating and coated the piece with 4000 Angstroms of aluminum via vacuum evaporation.

The conductivity was then probed along the sample.  The place where the conductivity sharply increased beneath 313 K appeared right at the interface of the PZT and its aluminum coat.

The paper involved can be found here.

It is important not to jump too swiftly to conclusions.  The measurements of conductivity could have been flawed, or they may not represent "true" superconductivity.  The paper has not yet been peer reviewed or published in a journal.  Given its impressive claims, and reportedly elementary process to achieve them, it will likely soon see peer review.

The idea of such a simple metal mix acting as what is essentially the holy grail of electronics, certainly sounds too good to be true.

However, if it does prove to truly be room temperature superconductivity, the discovery would revolutionize a number of industries including computing and power transmission.  One can only hope that this discovery -- or one in the near future -- is validated, so we can at last reap the benefits of superconductors without special equipment.

Some of the recent research into superconductors has focused on determining how they work, in an effort to come up with new designs.  To read more about this, check out our January 2008 andJuly 2008 pieces on this topic.



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RE: Hippo.
By 3DoubleD on 7/28/2010 12:47:07 PM , Rating: 2
It doesn't seem like what they did would great a superconductor at all. Coating material X with 400 nm of material Y isn't how you make a superconductor. If you measured the conductivity of such a sample, you are just measuring the conductivity of Material Y. No new material was created, unless there was some annealing step that this article forgot to mention. This seems doubtful at best.


RE: Hippo.
By Goty on 7/28/2010 1:30:25 PM , Rating: 5
If the arrangement of materials conducts with no resistance across the interface, then it is a superconductor.

It doesn't matter that this is a layered material instead of a doped material (as most superconductors are today), it is the behavior that makes it a superconductor, not the structure.


RE: Hippo.
By 3DoubleD on 7/28/2010 6:50:11 PM , Rating: 2
Firstly, the band structures of the metals have no bearing on the superconductivity of a material. Superconductivity is due to the interaction between electrons and phonons (lattice vibrations). An electron traveling through a superconductor will interact with the lattice and the corresponding phonon will link another electron to the first. The pairing of the two electrons (which are fermions), will create a boson. Bosons behave very differently than fermions, and the band structure of a given material becomes completely irrelevant at this point.

Secondly, a 4 point probe measurement of the sample involves contacting the SURFACE in 4 places. If the surface is aluminum or silver, then it would seem likely that is where the current will flow through as the field lines will be between the probes, not across the interface.

Finally, I agree that if there is zero resistance, it's a superconductor. I was merely expressing my doubt that the measurement was correct on the basis that their "superconductor" material is outside the regular definition. But, I'd love to be proven wrong! Bring on the superconducting revolution!


RE: Hippo.
By Goty on 7/28/2010 7:31:11 PM , Rating: 2
Congratulations, you have access to the internet!


RE: Hippo.
By Goty on 7/28/2010 7:39:52 PM , Rating: 2
Also, the band structure is very much important to a superconductor.

If you'd like to read up on the subject:

http://hyperphysics.phy-astr.gsu.edu/hbase/solids/...


RE: Hippo.
By 3DoubleD on 7/29/2010 12:17:34 AM , Rating: 2
Your link... to hyperphysics (what a great place to become an expert on physics..) discusses the energy gap (not the band structure) for cooper pairs. This is essentially the energy required to break up the pair. Thus the energy of phonons in the system cannot be greater than this value to maintain superconductivity. That is hardly a band structure in terms of the regular solid state physics definition.

Also, discussing BCS superconductivity is irrelevant. Type I superconductors (pure elemental materials) that follow BCS theory cannot be superconducting at room temperature. It is not possible due to the same energy gap that you reference. Type II superconductors (Cuprates) MIGHT one day be superconductive at room temperature, but to date it hasn't been achieved. The underlying mechanism for superconductivity in Type II superconductors is still debated, but it is not the same simple BCS theory. What is described in this article is certainly not a Type II (cuprate), which is what I was getting at in my last post. Unless all of those incredibly smart solid state physicists since the 80s completely forgot about PZT, I doubt this is anything but a hoax. The addition of pure aluminum makes this even more suspect since aluminum has one of the lower critical temperatures.


RE: Hippo.
By Goty on 7/29/2010 8:51:00 AM , Rating: 2
When you're getting all of your information from Wiki, hyperphysics is an amazing source. ;)


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