Cottrell Scholar Awards - 2014
Superconductivity: From Discovery to Rational Design
McQueen is attempting to synthesize and test new high-temperature superconducting (HTS) materials. As part of this effort, he is also trying to advance our understanding of how this amazing phenomenon works, and determine whether a room- temperature superconductor is really possible.
Superconductivity, a phenomenon in which a material carries an electrical current with zero resistance – that is, no loss of current to heat or other pathways – is increasingly essential to technologies such as microwave communications, advanced MRI machines, and even the electromagnets in the Large Hadron Collider.
Superconductivity occurs at extremely low temperatures. It was first observed in 1911, in metallic mercury below 4 K (−452 °F).
The discovery of a room-temperature superconductor would be revolutionary. Substituting the copper wires in our power grid with superconducting wires would entirely cut transmission losses and virtually eliminate power problems in high-density areas such as Manhattan.
This goal, however, remains elusive; no one has ever found a room-temperature superconductor, and scientists don’t even really understand how most superconductors work.
In 1986 scientists discovered the first of the so-called “high-temperature” superconductors (HTS). The term “high temperature” is somewhat misleading – physicists and materials scientists define HTS as occurring above 35 K (-397 ºF) and beyond the boiling point of liquid nitrogen (-321 ºF). In recent years HTS has been observed at temperatures as high as 138 K (−211 °F).
“We seek to develop rational design principles for new and improved superconductors, materials that carry a direct electrical current with zero loss,” McQueen said.
To better understand these unique substances, he is working to synthesize and characterize new materials that test the predictive capabilities of two new, highly complex theories regarding the origins of HTS.
One of those theories is a modified version of a long-standing theory holding that HTS occurs as the result of the interaction of electrons and “phonons,” vibrations in the crystal-lattice structure of certain superconducting materials. The other theory has to do with “antiferromagnetisim,” which occurs when the magnetic poles of atoms or molecules align in a regular pattern with neighboring poles pointing in opposite directions.
The Cottrell Scholar Award will also help fund McQueen’s goals as a chemistry teacher to expose students to hands-on experimentation. His is creating a new integrated lecture and laboratory course, Chemical Structure and Bonding, for second-semester freshmen. The course is intended to develop students’ laboratory skills, particularly the ability to take concepts from “bookwork” and apply them in the laboratory.