Monday, April 03, 2017

Alexei Abrikosov, Nobel Laureate in Physics, Dies at 88

Alexei Abrikosov in his office at Argonne National Laboratory in Illinois in 2003, the year he won the Nobel Prize in Physics. CreditKevin Tanaka/Getty Images
Alexei Abrikosov, who shared the Nobel Prize in Physics in 2003 for important insights into how certain materials conduct electricity without resistance, died on Wednesday at his home in Sunnyvale, Calif. He was 88.
His death was announced by Argonne National Laboratory in Illinois, where he had worked as a scientist. His son-in-law, Gary Micchelli, said the cause was a heart attack.
For decades, physicists have been fascinated and baffled by superconductors — materials, discovered in the early 20th century, that when chilled to very low temperatures allow electrical current to flow through effortlessly.
In 1950, two Soviet physicists, Vitaly L. Ginzburg and Lev Landau, came up with a mathematical model that described the behavior of a superconductor near the temperature at which the electrical resistance fell to zero. The theory largely matched what had been observed in experiments when elements like mercury and lead became superconducting.
One property of a superconductor is that it blocks out magnetic fields, and when scientists placed the earliest known superconductors in magnetic fields strong enough to push through the surface, they ceased to be superconducting.
But Dr. Abrikosov, a student of Dr. Landau’s who was then at the Institute for Physical Problems in Moscow, was intrigued by data for alloys made of different elements. These also turned into superconductors at low temperatures, but did not follow the pattern of the other materials, continuing to be superconducting when faced with strong magnetic fields.
“For me, the inspiration was always experiment,” Dr. Abrikosov said in a 2003 interview after winning the Nobel. “Some experimental facts which were strange could not get an immediate explanation, and so on.”
Pondering the Landau-Ginzburg equations, he discovered a solution that Dr. Ginzburg and Dr. Landau had missed.
His theory predicted that in the alloys, a lattice of tunnels, or vortices, could form in the superconductor, with the magnetic fields passing through them, like ropes pushed through the holes of Swiss cheese. The material around the vortices remains superconducting.
His solution describes what are now known as Type II superconductors, which continue to act as superconductors even in much stronger magnetic fields. The earlier superconductors like lead and mercury that failed in modest magnetic fields are Type I.
A decade later, experiments verified Dr. Abrikosov’s predictions of vortices.
Michael Norman, division director of materials science at Argonne, gave the analogy of hitting a table with a hammer. A Type I superconductor is like a table with brittle top. Hit hard, and it shatters to pieces and collapses. A Type II superconductor is like a tabletop made of a material where the hammer punctures a hole, but the table is still standing.
“The holes are the vortices,” Dr. Norman said. “What’s left is the superconductor.”
Superconductors have proved most useful when made into wires and wrapped into coils to generate powerful magnetic fields for applications like M.R.I. machines in medicine and giant particle accelerators in physics that delve into the smallest bits of matter. All these use Type II superconductors.
“Those are the ones that go into everything of technological significance,” Dr. Norman said.
Alexei Abrikosov was born in Moscow on June 25, 1928, the son of two physicians. He attended the Institute for Power Engineers before transferring to the physics department at Moscow State University. After completing a master’s degree in 1948, he studied at the Institute for Physical Problems and completed his doctoral degree there in 1951.
Dr. Abrikosov worked at several Moscow institutes, including as director of the Institute for High-Pressure Physics, part of the Russian Academy of Sciences. He moved to the United States to take a position at Argonne in 1991. He became an American citizen in 1999.
Survivors include his wife, Svetlana; a daughter, Natalia; two sons, Alexei and Michael; and four grandchildren.
Dr. Abrikosov was a member of the National Academy of Sciences, a foreign member of the Royal Society of London, a member of the Russian Academy of Sciences and a fellow of the American Physical Society.
He shared the Nobel with Dr. Ginzburg and Anthony J. Leggett, a London-born physicist at the University of Illinois at Urbana-Champaign.
Dr. Abrikosov never went back to his native country. Having grown up in an oppressive Stalinist society, he worried that officials would somehow prevent him from leaving again, Dr. Norman said.
In 1993, after the breakup of the Soviet Union, Dr. Abrikosov drew criticism for saying that the only way to maintain Russian science was for the West “to help all the talented scientists leave Russia and to ignore the rest.”
An opinion article quoting Dr. Abrikosov’s views appeared in The New York Times, prompting angry replies.
“As you can imagine, this didn’t go over well with the Russian community,” Dr. Norman said. “He was not shy about stating his opinions.”

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