"Superconductivity was more difficult to solve, and it required some radically new concepts," he once said.

His work on superconductivity was done with two graduate students, Leon Cooper, now at Brown University, and J. Robert Schrieffer, now at the University of California at Santa Barbara. The three shared the Nobel Prize in Physics in 1972.

The morning the second prize was announced, Dr. Bardeen almost missed a champagne celebration in his honor because of a misbehaving spinoff of his first prize-winning invention. He was unable to get his electronically controlled garage door to open. Colleagues at the university had to send a car to take him to the campus. Persistence 'Pays Off'

Noting that it had taken nearly two decades to develop the superconductivity theory, Dr. Bardeen told friends, "I'd say you've got to believe in persistence -- it sometimes pays off."

John Bardeen was born May 23, 1908, in Madison, Wis., the son of a dean of the medical school at the University of Wisconsin. He received his bachelor's and master's degrees in electrical engineering at the university and, after working three years as a geophysicist at Gulf Research Laboratories in Pittsburgh, earned a doctorate in mathematical physics at Princeton University in 1936.

Later, he held a fellowship at Harvard University, taught at the University of Minnesota and was a physicist with the Naval Ordnance Laboratory during World War II. After the war, he joined the Bell Laboratories as a researcher in solid-state physics. From 1951 until his retirement in 1975, he was a professor of electrical engineering and physics at the University of Illinois.

Dr. Bardeen also served on the President's Science Advisory Committee from 1959 to 1962 and on the White House Science Council in the early 1980's. His honors included the National Medal of Science in 1965, the Presidential Medal of Freedom in 1976, and the Lomonosov Prize from the Soviet Academy of Sciences in 1988. He received 16 honorary degrees and was elected to the National Academy of Sciences, the National Academy of Engineering and the American Philosophical Society.