ITHACA, N.Y.—Robert C. Richardson, a Cornell University professor who shared a Nobel Prize for a key discovery in experimental physics, has died. He was 75.

Richardson died Tuesday in Ithaca from complications of a heart attack, Cornell said Wednesday.

He and fellow Cornell researchers David Lee and Douglas Osheroff were awarded the Nobel for 1996 for their 1971 work on low-temperature physics involving the isotope helium-3, which has contributed to research ranging from the properties of microscopic matter to astrophysics.

Richardson was born in Washington, D.C., earned his bachelors and masters degrees in physics at Virginia Polytechnic Institute and a doctorate at Duke University, where he studied with the physicist Horst Meyer and later served as a trustee.

He joined Cornell in 1968 and was named Floyd R. Newman Professor of Physics in 1987. He was also Cornell's first provost for research from 1998 to 2003.

"Bob Richardson was an extraordinary physicist who used his deep understanding of the scientific enterprise to shape the course of research at Cornell and nationally," said Cornell President David Skorton.

As co-author of the 2005 National Academy of Sciences report "Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Economic Future," Richardson called for the U.S. to ensure it remains globally competitive in science and technology.

Lee, now a physics professor at Texas A&M University, and Osheroff, a professor emeritus at Stanford University, both praised Richardson as a role model and mentor for colleagues and graduate students.