Alexander Müller (1927–2023)

Müller, who has died aged 95, demonstrated the transition to superconductivity at a temperature of 35 K (35 °C above absolute zero) in a class of ceramic known as cuprates, raising the tantalizing possibility of frictionless power distribution, levitating trains and other applications. During a two-year secondment to IBM's Thomas J. Watson Research Center in Yorktown Heights, New York, in 1978, he seized on superconductivity as a promising research area - made more tractable by emerging work in critical phenomena, such as phase transitions. In 1986, they observed superconductivity in lanthanum barium copper oxide with a transition temperature of around 35 K, more than 10 K above the previous highest transition temperature.