John Robert Schrieffer, born in 1931, American physicist and Nobel Prize winner. Schrieffer shared the 1972 Nobel Prize in physics with American physicists Leon N. Cooper and John Bardeen for the first general explanation of superconductivity, a complete lack of electrical resistance in a substance.

Born in Oak Park, Illinois, Schrieffer received his B.S. degree in physics from the Massachusetts Institute of Technology (MIT) in 1953. He earned his M.S. degree in 1954 and Ph.D. degree in 1957 from the University of Illinois. After he received his doctoral degree, he studied briefly in England and Denmark under a National Science Foundation (NSF) fellowship. Schrieffer taught physics at the University of Chicago from 1957 to 1960, at the University of Illinois from 1959 to 1960, and at the University of Pennsylvania in 1962. He taught at Cornell University from 1969 to 1975, and was a professor at the University of California at Santa Barbara from 1975 to 1992. Since 1992, Schrieffer has been a professor at Florida State University.

To explain superconductivity, Bardeen, Cooper, and Schrieffer had to explain how any substance could achieve perfect conductivity. Most metals lose resistance as they are cooled because the thermal vibrations of the atoms, which are a cause of resistance, slow down. But these vibrations will not cease completely until the substance is cooled to absolute zero (-273° C/-460° F), a temperature that cannot be obtained. Superconducting material reaches zero resistance suddenly and at temperatures above absolute zero.

In 1956 Cooper showed that electrons carrying current through a superconductor acted strangely—instead of repelling each other because of their like charge, pairs of electrons actually seemed to be bound together. At low enough temperatures, the atomic vibrations in the crystal structure of the metal allow one of the electrons to draw the positively charged metal atoms to itself. This creates a concentration of positive charge, which attracts the second electron. Such a pair of electrons is now called a Cooper pair.

At the University of Illinois in 1956 and 1957 Schrieffer and Bardeen sought to apply this model of electron behavior to a large percentage of the electrons in a superconductor. They collaborated with Cooper, also at the University of Illinois, to show that the interaction between Cooper pairs forces many of the free electrons to march along in formation. Below a certain temperature, the forces holding the pairs of electrons together are stronger than the thermal vibration of the atoms. Without anything to slow down the electrons, there is no resistance.

This theory of superconductivity is known as the Bardeen-Cooper-Schrieffer (BCS) theory. It has led to the development of superconductors that can operate at higher temperatures and that can be used to make strong electromagnets that use little power. Such magnets have many potential uses, including applications in quantum mechanics, biology, generation of electricity, and many other fields.

In addition to the Nobel Prize, Schrieffer has received many honorary degrees and other awards. He became the president of the American Physical Society in 1996.