[sci.electronics] New superconducting

schumann@puff.UUCP (02/17/87)

This morning (Tuesday), I saw a small story on Headline News about some
scientist at a Houston University (I think) that has made a great
advancement in the practicality of superconducters.

Well, What's the scoop?  What did he do, how will it affect *us*, and
what should be known, etc, etc....

Chris Schumann				schumann@puff.wisc.edu

dplatt@teknowledge-vaxc.UUCP (02/18/87)

Based on what I saw in the San Jose Mercury-News, a research team has
developed an alloy which begins exhibiting superconducting behavior at
an extremely high temperature (well above the boiling-point of liquid
helium, and well below the boiling point of liquid nitrogen) at
"normal" pressures.  If I've got these details correctly, then it is
indeed a major breakthrough... all previous "high"-temperature
semiconductors have required extremely high pressures to operate (e.g.
several thousand or million PSI), and none have switched to
semiconducting behavior at liquid-nitrogen temperatures.

In short, it means that semiconductive circuits (e.g.
magnetic-levitation systems) can now be refrigerated with liquid
nitrogen, which is MUCH cheaper and easier to handle than liquid
helium.  This should increase the practical use of semiconductors in
maglev systems, power-generation, lasers, etc. by an order of
magnitude.

ch@well.UUCP (02/19/87)

In article <503@puff.WISC.EDU> schumann@puff.WISC.EDU (Christopher Schumann) writes:
>This morning (Tuesday), I saw a small story on Headline News about some
>scientist at a Houston University (I think) that has made a great
>advancement in the practicality of superconducters.

What you are referring to, I believe, is detailed in Science magazine,
Vol. 235, 30 January, 1987. There are two seperate articles, pp. 531, and
567.

Briefly, the article details the research of several independent teams
who have reportedly observed the onset of superconductivity at temperatures
as high as 70 degrees Kelvin. The Houston team has observed an onset temperature
of 52 degrees Kelvin in a material that became fully superconductive at 25 K.
The material used was a lathanum-barium-copper-oxygen compound under hydrostatic
pressure.

Scientifically, these findings are notable because they seem to indicate
that superconductivity may be possible at at temperatures higher than those
predicted by previous theories. Practically, the availability of inexpensive
materials that superconduct at much higher temperatures than previously
known materials will key the development of motors, coils, magnets, etc.,
of unprecedented efficiency, size, and power.
-- 
	Chris Hayes
			UUCP: ucbvax!dual!well!ch
			 OR : {hplabs, ptsfa, lll-lcc}!well!ch

haddock@ti-csl.UUCP (02/19/87)

In article <503@puff.WISC.EDU> schumann@puff.WISC.EDU (Christopher Schumann) writes:
>This morning (Tuesday), I saw a small story on Headline News about some
>scientist at a Houston University (I think) that has made a great
>advancement in the practicality of superconducters.
>
>Well, What's the scoop?  What did he do, how will it affect *us*, and
>what should be known, etc, etc....
>

I heard the same thing on one of the local radidio stations here.  I
was still half asleep so the numbers are probably wrong but....  It
appears that the researchers have found a way to have superconductance
at relatively "high" temperatures.  What they meant by "high" is
they've found a way to use "cheap" liquid nitrogen to acheive
superconductance.  The great idea behind this is that liquid nitrogren
is about 10X cheaper than the liquid helium(?) and superconductance is
attained at 20X the temperature.  No immediate benefits (for the
public) are perceived but with more research hopefully a more
efficient means of transmitting electrical energy will be found via
the use of superconductance.

					-Rusty-
-- 
================================================================
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Computer Science Center, CRD&E +++ CSNET: Haddock@TI-CSL
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daveh@cbmvax.UUCP (02/19/87)

> In-reply-to: schumann@puff.WISC.EDU's message of 17 Feb 87 19:27:10 GMT
> 
> Based on what I saw in the San Jose Mercury-News, a research team has
> developed an alloy which begins exhibiting superconducting behavior at
> an extremely high temperature (well above the boiling-point of liquid
> helium, and well below the boiling point of liquid nitrogen) at
> "normal" pressures.

I never saw the article, but about a month ago a friend who works with
superconducting magnets at MIT mentioned such a breakthough.  The new
superconducting material will superconduct at around 40K, and its 
probably going to be much cheaper to make than the previous record
holder, which superconducts at around 20K.  Because of the cost of the
20K superconductor, they've done little to no magnetics research with it,
they're still well into liquid He and occasionally He3.
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dave Haynie	{caip,ihnp4,allegra,seismo}!cbmvax!daveh

      You too can put the POWER of RANDOM NUMBERS to work for you!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

jewett@hpl-opus.UUCP (02/19/87)

   A recent New York Times article (in the SF Cronicle) says that Chu and Wu
   (Univ. Houston and Univ. Alabama resp.) have reported supercondutivity
   at -283F which is 98 kelvins.  Their work is to be reported soon in
   Phys. Rev. Lett.

   The latest Scientific American reported that the 70K claim from China had
   been withdrawn.

piner@pur-phy.UUCP (02/22/87)

In article <1439@cbmvax.cbmvax.cbm.UUCP> daveh@cbmvax.cbm.UUCP (Dave Haynie) writes:
>> In-reply-to: schumann@puff.WISC.EDU's message of 17 Feb 87 19:27:10 GMT
>> developed an alloy which begins exhibiting superconducting behavior at
>> an extremely high temperature (well above the boiling-point of liquid
>> helium, and well below the boiling point of liquid nitrogen) at
>> "normal" pressures.
>superconducting magnets at MIT mentioned such a breakthough.  The new
>superconducting material will superconduct at around 40K, and its 
>probably going to be much cheaper to make than the previous record
>holder, which superconducts at around 20K.  Because of the cost of the
>20K superconductor, they've done little to no magnetics research with it,
>they're still well into liquid He and occasionally He3.
>-- 
  This is old news. Things are happening very fast right now. The latest
superconductor transition is around 90K, well above liquid N2. Rumor
has it that a 150K transition has been seen. Rumor also has it that a
"dry ice" superconductor may be possible. There is a rub however. These
materials are oxides. No one knows how to make a wire out of them. Yet.

					Richard Piner
					piner@galileo.physics.purdue.edu

witters@fluke.UUCP (02/24/87)

Does anyone else remember an article some years back in Electronics about a
possible room temperature superconductor?  Apparently someone used a 4 terminal
Ohm meter to measure the resistance of some titanium alloy they were trying to
make ductile, and it indicated zero resistance.  However, this is only one
characteristic of a true superconductor, and the article said that further
experiments would have to be done to determine if the material would repel a
magnetic field.  I never saw a followup article.  If I remember correctly, the
article appeared sometime in 1979 or 1980.  Since I haven't seen anything more
about this, I can think of three possibilities.

	1.	The experiments were performed, and it turned out that the
		material wasn't a superconductor.  It seems to me that if this
		was the case, there would have been a followup article.

	2.	The NSA classified the research.  If I remember correctly, the
		research was originally being done for the Air Force (titanium,
		remember?), so it would be easy for the stuff to get
		classified.

	3.	The article appeared in the April issue.  If so, I think there
		should have been a followup revealing the article as a prank.

-- 
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