In Nobel terms, the 1987 physics prize to Dr. Müller and fellow IBM researcher J. Georg Bednorz was a rare fast-track decision. Just a year earlier, they had published findings from experiments that relied on elements in a ceramic mix for use as a superconductor — the name for any material where electrons move so orderly that no heat or energy is lost, unlike, for example, commercial wiring.

Superconductivity had been studied since 1911, when Dutch researcher (and later Noble laureate) Heike Kamerlingh Onnes observed the phenomenon in tin, mercury and lead at temperatures approaching absolute zero, or near minus-460 degrees Fahrenheit. By the 1970s, researchers had created superconductivity conditions in elements at about minus-424 degrees.

The ceramic mix of Dr. Müller and Bednorz — lanthanum barium copper oxide — was a superconductor at slightly higher temperatures, around minus-400 degrees.

That small advance had major significance. Other scientists quickly explored other ceramics that were superconductors at higher temperatures. Each step meant the potential for greater practical applications, such as MRI imaging and the feasibility of Maglev trains (as superconductors can create powerful magnetic fields).

The Nobel Committee in 1987 lauded Dr. Müller and Bednorz for their “audacity to concentrate on new paths” and said that it merited “one of the most immediate decisions in the history of the award.”

For Dr. Müller, it was an idea that struck while he was mulling his post-retirement life.

It was 1983, he recalled, and he was on a walk when, somehow, his thoughts turned to using ceramic compounds as a superconductor rather than the metal-based materials in most common use, he said. The notion, however, seemed too simple to be true. He said the initial concept was shared only with a few colleagues.

That way “we could bury it in a close family circle” if the theory didn’t pan out, he told a University of Minnesota gathering in 1990.

Instead, the experiments were encouraging. So good, in fact, Dr. Müller thought something was missed. “Where did we make a substantial blunder?” he wondered. But the results were confirmed repeatedly.

Superconductivity is essentially all about order. Electrons pair up and move with no resistance through a superconductor environment, rather than shifting around and expending energy in, for example, electrical circuits or semiconductors in computer chips.

“For basic research, this was certainly a breakthrough,” said Hugo Keller, professor emeritus in physics at the University of Zurich, noting Dr. Müller’s work with ceramics in a video interview for the university. “Nobody expected to find superconductivity in such compounds.”

Still, major obstacles remain for widespread commercial applications beyond the current main uses in MRI machines and short-distance Maglev rail links in Asia and Europe. Superconductor cables also have been used in magnets at the CERN Large Hadron Collider in Switzerland and the Holbrook Superconductor Project on Long Island.

The brittleness of ceramics poses challenges for use as wires. The temperatures needed for ceramics superconductors, now at about minus-220 degrees, are also well beyond normal cooling systems and need a flow of liquid nitrogen. (Curiously, scientists refer to the field as “high-temperature” superconductivity.)

Dr. Müller said it took only two hours to persuade Bednorz to join him in experimenting with ceramics in 1983. The harder part was keeping it secret from IBM colleagues and others in case it went nowhere.

“We did it,” he said in a 2004 interview, “under the table.”

‘Look for the extraordinary’

Karl Alexander Müller was born on April 20, 1927, in Basel, Switzerland, as the only child of parents who soon moved to Salzburg, Austria, where Dr. Muller’s father studied music.

After his parents separated, Dr. Müller and his mother moved to Dornach, Switzerland, south of Basel and then to Lugano, in Switzerland’s Italian-speaking region where Dr. Müller learned Italian in school. (He long preferred to use only the initial of his first name on public documents.)

He was 11 when his mother died, and he finished his high school education at Evangelical College, a boarding school in eastern Switzerland, Dr. Müller recounted in a biographical essay for the Nobel Committee.

World War II was raging around neutral Switzerland, and the student followed events over the radio. Dr. Müller had received a radio kit as a gift from his mother when he was 9, and he became fascinated with building and repairing radios at school.

After compulsory military service, he studied at the Swiss Federal Institute of Technology in Zurich. The class had swelled with students interested in nuclear physics following the U.S. atomic bombings on Hiroshima and Nagasaki in Japan. “We were called the ‘atombomb semester,’” he wrote.

Dr. Müller graduated in 1952 from the Zurich institute with a physics degree and received his doctorate in 1958. At the Battelle Memorial Institute in Geneva from 1958 to 1963, he worked in the magnetic resonance group. He said he never forgot the encouragement of the Battelle general manager, Hugo Thiemann. “His ever-repeated words, ‘one should look for the extraordinary’ made a lasting impression on me,” Dr. Müller wrote.

In 1963, he took a research position at IBM while also teaching at the University of Zurich. He stepped down as a team manager for IBM in 1985, but he maintained a role in the lab as an IBM fellow and later in emeritus status until 1998.

Dr. Müller married Ingeborg Winkler in 1956. Survivors also include two children and three grandchildren.

During the winter, Dr. Müller often broke away from lab work to spend time in the mountains to ski. After a good snow in the Swiss Alps, colleagues knew not to schedule any meetings.

“My best dreams are those where I am skiing downhill in good powder snow,” he once said. “Whenever I have this dream, I am convinced that I am totally okay.”