Superconductivity Discovered in 1911

Heike Kamerlingh Onnes (21 September 1853 – 21 February 1926) was a Dutch physicist and Nobel laureate. He exploited the Hampson-Linde cycle to investigate how materials behave when cooled to nearly absolute zero and later to liquefy helium for the first time. His production of extreme cryogenic temperatures led to his discovery of superconductivity in 1911: for certain materials, electrical resistance abruptly vanishes at very low temperatures.

                                                       Heike Kamerlingh Onnes in 1913
                                                          (from the Nobel Foundation)

Career at University of Leiden

From 1882 to 1923 Kamerlingh Onnes served as professor of experimental physics at the University of Leiden. In 1904 he founded a very large cryogenics laboratory and invited other researchers to the location, which made him highly regarded in the scientific community. The laboratory is known now as Kamerlingh Onnes Laboratory.  Only one year after his appointment as professor he became member of the Royal Netherlands Academy of Arts and Sciences.

Liquifaction of Helium

On 10 July 1908, he was the first to liquefy helium, using several precooling stages and the Hampson-Linde cycle based on the Joule-Thomson effect. This way he lowered the temperature to the boiling point of helium (−269 °C, 4.2 K). By reducing the pressure of the liquid helium he achieved a temperature near 1.5 K. These were the coldest temperatures achieved on earth at the time. The equipment employed is at the Boerhaave Museum in Leiden.

Superconductivity

In 1911 Kamerlingh Onnes measured the electrical conductivity of pure metals (mercury, and later tin and lead) at very low temperatures. Some scientists, such as William Thomson (Lord Kelvin), believed that electrons flowing through a conductor would come to a complete halt or, in other words, metal resistivity would become infinitely large at absolute zero. Others, including Kamerlingh Onnes, felt that a conductor's electrical resistance would steadily decrease and drop to nil. Augustus Matthiessen pointed out when the temperature decreases, the metal conductivity usually improves or in other words, the electrical resistivity usually decreases with a decrease of temperature.

On 8 April 1911, Kamerlingh Onnes found that at 4.2 K the resistance in a solid mercury wire immersed in liquid helium suddenly vanished. He immediately realized the significance of the discovery (as became clear when his notebook was deciphered a century later).  He reported that "Mercury has passed into a new state, which on account of its extraordinary electrical properties may be called the superconductive state". He published more articles about the phenomenon, initially referring to it as "supraconductivity" and, only later adopting the term "superconductivity".

Kamerlingh Onnes received widespread recognition for his work, including the 1913 Nobel Prize in Physics for (in the words of the committee) "his investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium".

Legacy

[A building and a laboratory at Leiden University have been named for Onnes. In addition:]

·         The Onnes effect referring to the creeping of superfluid helium is named in his honor.

·         The crater Kamerlingh Onnes on the Moon is named after him.

·         Onnes is also credited with coining the word "enthalpy".

·         Onnes' discovery of superconductivity was named an IEEE Milestone in 2011.

Honors and Awards

• Matteucci Medal (1910)
• Rumford Medal (1912)
• Nobel Prize in Physics (1913)
• Franklin Medal (1915)

https://en.wikipedia.org/wiki/Heike_Kamerlingh_Onnes