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Alexander Müller (1927–2023)


Karl Alexander Müller, Swiss Nobel Laureate in Physics (1987).

Credit score: Sueddeutsche Zeitung Photograph/Alamy

In 1986, Alexander Müller and his pupil Georg Bednorz found high-temperature (high-Tc) superconductivity. Solely a 12 months later, their discovery earned them the 1987 Nobel Prize in Physics. Superconductivity, wherein all electrical resistance disappears beneath a crucial temperature, had been recognized since 1911, however primarily in metals and alloys cooled to inside a level or two of absolute zero. Müller, who has died aged 95, demonstrated the transition to superconductivity at a temperature of 35 Ok (35 °C above absolute zero) in a category of ceramic often known as cuprates, elevating the tantalizing risk of frictionless energy distribution, levitating trains and different purposes.

The physics world, initially sceptical, was gripped by pleasure. On the American Bodily Society’s March 1987 assembly, later dubbed the ‘Woodstock of physics’, in reference to the 1969 music competition, greater than 2,000 physicists crammed right into a lodge ballroom to listen to a panel focus on the brand new superconductors. By this time, others had discovered associated supplies with transition temperatures near 100 Ok. Excessive-Tc superconductivity has since been utilized in magnetic resonance imaging methods and in different specialised purposes — but theorists proceed to hunt a passable clarification for the way it works.

Born in Basel, Switzerland, in 1927, Müller caught the science bug in childhood, when his mom gave him a vacuum-tube radio package. On the Swiss Federal Institute of Know-how in Zurich, he attended seminars given by the Nobel-prizewinning theoretical physicist Wolfgang Pauli. For his doctoral thesis underneath Georg Busch, he used electron paramagnetic resonance spectroscopy to review {the electrical} and magnetic properties of quite a lot of solids.

In 1958, Müller moved to the Geneva department of the Battelle Institute, a non-profit industrial analysis and improvement group headquartered in Columbus, Ohio. He studied radiation harm in graphite, in response to the 1957 accident on the Windscale nuclear reactor in the UK. Partly owing to wreck in its graphite moderator, the reactor had overheated and caught hearth, releasing a radioactive plume throughout Europe. Müller’s work on neutron-irradiated graphite, revealed in Bodily Evaluation in 1961 (Ok. A. Müller Phys. Rev. 123, 1550–1552; 1961), caught the eye of the director of IBM Analysis Zurich in Rüschlikon. He lured Müller away from Geneva in 1963 to work on solid-state issues related to IBM’s funding in digital computing.

Müller spent the remainder of his profession at IBM Rüschlikon. He established himself as a world-leading knowledgeable on perovskites — oxides with a particular, symmetrical crystal construction that makes them appropriate for a variety of engineering purposes, together with microelectronics and photo voltaic cells.

Müller took a parallel appointment as a professor on the College of Zurich in 1970, and have become director of the physics division at IBM Rüschlikon in 1973. Throughout a two-year secondment to IBM’s Thomas J. Watson Analysis Heart in Yorktown Heights, New York, in 1978, he seized on superconductivity as a promising analysis space — made extra tractable by rising work in crucial phenomena, comparable to part transitions. After his return to Zurich, he was named an IBM Fellow and given freedom to pursue unbiased analysis. He took up high-Tc superconductivity in earnest, and, in 1983, started his collaboration with Bednorz, who shared his fascination with perovskites.

The pair started on the lookout for superconductivity in perovskite-like ceramics, pushed by theoretical and experimental hints, but in addition, as Müller recalled, by an “atavistic sort of feeling” of their suitability. In 1986, they noticed superconductivity in lanthanum barium copper oxide with a transition temperature of round 35 Ok, greater than 10 Ok above the earlier highest transition temperature.

Cuprates and different high-Tc superconductors are tougher to work with than are metallic alloy low-Tc superconductors, and they’ve few sensible purposes as but. In addition they don’t obey the Bardeen–Cooper–Schrieffer concept, which describes how electrons work together with phonons (packets of vibrational vitality) in typical superconductors. Candidate theories emerged swiftly after 1986, however at this time high-Tc superconductivity stays maybe essentially the most notable unsolved drawback in condensed-matter concept.

Already aged 60 when he obtained the Nobel prize, Müller continued his work on superconductivity, as an IBM fellow till 1992 and on the College of Zurich till 1994, when he was awarded emeritus standing. His analysis, which he carried on effectively into his eighties, shed additional mild on the behaviour of high-Tc superconductors, and positioned main constraints on candidate theories of the phenomenon.

Müller’s method to science mirrored the expedience of business, the place the excellence between fundamental and utilized analysis holds little sway. He drew concepts from wherever he may discover them, and shortly deserted approaches that he discovered too constraining. He was equally completely satisfied to take inspiration from unconventional sources. He recalled being drawn to perovskites as a result of their symmetrical construction reminded him of the mandalas of Japanese religions, to which he attributed a deep, nearly religious significance.

Alex was an avid sportsman who skied into his eighties and most well-liked the slopes to the highlight. Like his nine-year-old self constructing the radio, he approached physics with the perspective that he needed to discover out for himself. He flouted conventions that solid doubt on his instincts about superconductivity, declaring, “I simply don’t discuss to the theoreticians. They only held me again.” The fruits of his curiosity proceed to outline a big space of condensed-matter physics and its purposes.

Competing Pursuits

The writer declares no competing pursuits.

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