Schrieffer, John Robert (1931-2019), an American scientist, shared the 1972 Nobel Prize for physics with fellow-Americans John Bardeen and Leon Cooper for their jointly developed theory of superconductivity. The theory, often called the “BCS theory” after the first initial of each of the three scientists’ last names, explains superconductivity, in which the electrical resistance of a substance disappears completely at very low temperatures.
Schrieffer was born on May 31, 1931, in Oak Park, Illinois. In 1949, he entered Massachusetts Institute of Technology (MIT), at first studying electrical engineering, and then majoring in physics. He became interested in solid-state physics at MIT, and began research in that area at the University of Illinois, in the department headed by John Bardeen. As a doctoral student, he worked with Bardeen and Cooper, studying superconductivity as both a theoretician and as an experimentalist. Schrieffer received his Ph.D. from the University of Illinois in 1957.
The type of superconductivity known at that time appeared in certain materials at temperatures a few degrees above absolute zero (-273.15 °C, -459.67 °F). Schrieffer showed how, in these circumstances, electrons could form “Cooper pairs” (named after his colleague), in which the motions of two electrons become linked by the mutual interaction of the negative charges and the positive charges of the array of atoms through which they move. Schrieffer extended this insight to all the electrons in the conducting material, showing that the motions of all the electrons became linked. Moving as one, they are not impeded by irregularities in the crystal structure that at higher temperatures give rise to resistance. The current flows freely and the material is described as a “superconductor.” The three workers developed these ideas into the BCS theory, which successfully explained low-temperature superconductivity.
From the late 1950’s to the 1990’s, Schrieffer worked at many institutions in the United States and Europe, much of his work being concerned with superconductivity. He was the chief scientist at the National High Magnetic Field Laboratory in Tallahassee, Florida, until he retired in 2006. High-temperature superconductivity was discovered in the mid-1980s. It appears in certain ceramic materials at temperatures that are relatively high–typically at the temperature of liquid nitrogen (77° Celsius or 139° Fahrenheit, above absolute zero). The BCS theory does not explain high-temperature superconductivity, and Schrieffer tried to develop a new theory to account for it.
In 2004, Schrieffer was involved in a serious automobile accident. Schreiffer, who was speeding at the time, crashed his car into a van, killing one of the van’s passengers. As a result, a judge sentenced Schrieffer to two years in prison for manslaughter in 2005. Schrieffer died on July 27, 2019.
