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Superconductivity with a Twist

March 9, 2011

Some experiments are so strange, you're sure that alcohol was involved. In some cases, the use of alcohol as a creativity enhancer is documented. The invention of the bubble chamber by Donald A. Glaser was one such story; but, alas, it's not true. Glaser was said to have gotten the idea for the bubble chamber while staring into a glass of beer. In 2006, Glaser said the story wasn't true, although he did use beer, unsuccessfully, in his early chamber experiments.[1] Glaser won the Nobel Prize in Physics in 1960.

Carlsberg Beer is important to the history of physics, since the Carlsberg Foundation supported Niels Bohr and his Institute of Theoretical Physics. This is now known as the Niels Bohr Institute.

Beer mug iconThe font of quantum mechanics.
Beer profits funded Niels Bohr.
(Image from Wikimedia Commons)

There's the famous experiment, attributed to Galileo, called the "wine-raiser," that demonstrates the difference in density between water and wine. This party trick was apparently well known in Galileo's time. A glass of water is placed over a glass of wine with a partition in between. The partition is shifted slightly to allow a flow of liquid between the glasses without turbulent mixing. Since wine is less dense than water, it will rise to the top, and the water will fall to the bottom. There a video of this here.

Tears of wine, also known as wine legs, is the phenomenon in which droplets fall from a ring of clear liquid at the top of a glass of wine of high alcohol content. Alcohol has lower surface tension than water, so wine will flow to regions of lower alcohol concentration. Alcohol, of course, evaporates faster than water, so any liquid on the sides of the glass will have low alcohol content. This liquid will draw other liquid up to it, and droplets will fall when too much liquid accumulates. It's a world of physics in a wine glass!

Now, to the strangeness. It seems like an illogical experiment, but a group of Japanese researchers at the National Institute for Materials Science, Tsukuba, Japan, decided to marinate their superconductors in wine.[2] Since this was Japan, they used Sake as well as red wine, and their marinade was hot, not cold. Their specimens were FeTe0.8S0.2, an example of the class of the new iron-based superconductors that have gotten a lot of buzz (pun intended), since magnetism has always been inimical to superconductivity. Such materials are superconducting only when left in the air for quite a few weeks, but the wine marinade sped things up to a single day.[2]

As described in a paper in Superconductor Science and Technology,[3] this process enhanced the superconductivity. They found that an ethyl alcohol-water mixture didn't work as well as the alcoholic beverages. Hot, red wine at 70o had the best affect, giving a superconducting transition temperature of 7.8 K. The implication is that it isn't merely the alcohol or water, but some other component. Red wine is red, of course, since it has iron in it.

The reason why letting these materials stand in air, or the recently-discovered wine soak, enhances the superconductivity isn't known, but it must modify the magnetic order of the iron atoms in some way. It was always thought that the oxygen in the air is what did the trick, and this might be the case also for the beverage soak.

As I wrote in a previous article (Van Gogh Versus the Sulfates, March 1, 2011) silverware tarnishes in air because of a reaction of its oxide with hydrogen sulfide (H2S) to form the black tarnish product, silver sulfide, Ag2S,
Ag2O + H2S -> Ag2S + H2O

Those of you sensitive to sulfites know that they're present as a preservative in wine. There seems to be some link here between exposure of the superconductors to air and exposure to wine. I recommend exposure to hydrogen sulfide (H2S) gas, and a carbon disulfide (CS2) soak as some other experiments.

References:

  1. Anne Pinckard, "Invention and History of the Bubble Chamber," The Berkeley Lab View, July 21, 2006.
  2. Japanese scientists use alcoholic drinks to induce superconductivity, Institute of Physics Press Release, March 7, 2011
  3. K Deguchi, Y Mizuguchi, Y Kawasaki, T Ozaki1, S Tsuda, T Yamaguchi and Y Takano, "Alcoholic beverages induce superconductivity in FeTe1 - xSx," Superconductor Science and Technology, vol. 24, no. 5 (May, 2011), Document 055008 (Published March 7, 2011).