The discovery that certain materials exhibit superconductivity at temperatures above 77 kelvin (minus 320 degrees Fahrenheit) in 1987 by a team of researchers at the University of Houston and the University of Alabama, led by Professor Paul C. W. Chu, now the Founding Director and Chief Scientist of the Texas Center for Superconductivity at the University of Houston (TcSUH), has been designated an IEEE Milestone in Electrical Engineering and Computing. A plaque emblematic of this designation was presented to the University of Houston at a ceremony held at the Hilton University of Houston Hotel on November 17th by Professor J. Roberto de Marca, President and CEO of the IEEE, and was accepted, on behalf of the University of Houston, by Dr. Renu Khator, Chancellor of the University of Houston System and President of the University of Houston.  The plaque has been permanently mounted in the lobby area of Science Research Building One, on the University of Houston campus, where the discovery of these materials was made in 1987. The IEEE Milestones in Electrical Engineering and Computing program honors significant technical achievements in technology areas that benefit humanity. This Milestone was the 149th to be approved by the IEEE Board of Directors since the IEEE Milestone Program was established in 1983.


 

Photograph of the IEEE Milestone in Electrical Engineering and Computing plaque that was presented to the University of Houston on November 17, 2014

The arrangements for the events associated with the dedication of the Milestone Plaque were made by the Texas Center for Superconductivity at the University of Houston (TcSUH), the IEEE Houston Section, and the IEEE Council on Superconductivity, and was were sponsored by the UH Division of Research, the UH Cullen College of Engineering, the UH College of Natural Sciences and Mathematics, and by the T.L.L. Temple Endowment. The proposal for the Milestone was initiated and submitted to the IEEE History Committee by Prof. Willis A. King, Emeritus Professor and Chair of the Computer Sciences Department at the University of Houston, who has been active in the IEEE Computer Society and in the IEEE Houston Section for many years.

Superconductivity is a very “exotic” behavior observed in certain materials that lose all of their electrical resistance when they are cooled below room temperature to very deep cryogenic temperatures. It was first observed in 1911 by Prof. Heike Kamerlingh Onnes and collaborators at the University of Leiden (The Netherlands) while measuring the resistance of mercury at temperatures just a few degrees above absolute zero (that is, minus 459.7 degrees Fahrenheit). In 2011, the discovery of superconductivity by Onnes and colleagues was designated an IEEE Milestone in Electrical Engineering and Computing and a plaque was dedicated in the building on the University of Leiden campus where the initial experiments had been done. Superconductivity has been observed in more than 10,000 elements, compounds, mixtures and alloys with the highest known transition temperature, to date, of minus 200 degrees Fahrenheit.  A comprehensive microscopic theory of superconductivity, which has been quite successful in explaining the behavior of most of the low-temperature superconductors, was proposed in 1957 by John Bardeen, Leon Cooper and Robert Schrieffer (the so-called “BCS” theory), for which they received the Nobel Prize in Physics in 1972. A total of five Nobel Prizes in Physics have been awarded to scientists for their research in superconductivity. The status of superconducting materials changed dramatically in 1986 following the work of Mueller and Bednorz (IBM, Switzerland) who reported the discovery of a copper oxide-based ceramic material that exhibited superconductivity at a temperature of 35 K. The discovery that Y-123 (the compound yttrium-barium-copper-oxide, with formula Y1Ba2Cu3O7) exhibits superconductivity above the boiling point of liquid nitrogen (77K, or minus 321 Fahrenheit) by a team of researchers. The significance of having superconductivity at temperatures above the boiling point of liquid nitrogen is the drastically reduced cost and complexity of the refrigeration needed to cool the superconductor to temperatures below their superconducting transition temperature. Prior to the discoveries of the Houston group, most of the known superconductors had to be cooled to temperatures near the boiling point of liquid helium (4 kelvin or minus 452 degrees Fahrenheit).

The cost of maintaining an object at or near liquid nitrogen temperatures is at least a factor of 100 smaller than the cost of providing a 4 kelvin environment. This reduction in cost applies for either technique of cryogenic cooling: use of a liquid cryogen (liquid helium for 4 kelvin or liquid nitrogen for 77 kelvin) or use of a closed cycle cryogenic refrigerator (a cryocooler). However, the high-temperature superconducting materials tend to be ceramic (and thus very brittle) in nature and very difficult to make into wires and cables for high power applications, or into electronic devices and circuits. As a result, the excitement of reduced cost of operation has to be balanced against the challenges of making useful circuits and systems from these materials. In the last decade, however, great progress has been made in the fabrication of HTS wire, which can now be made in kilometer lengths.

On the morning of November 17, before the actual presentation of the plaque to the University of Houston, a special IEEE Milestone Community Lecture series was held at the Hilton University of Houston Hotel which was open to the general public, including high school students. The series was called “Superconductivity above 77 K in Y-123 – History, Science and Applications,” and was chaired by Dr. John Spargo, Past President of the IEEE Council on Superconductivity. The first speaker in this session was Prof. Paul C. W. Chu, who spoke on “High-Temperature Cuprate Superconductor: A History.” He reviewed the status of superconducting materials.