A magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen / LANLOn April 8, 1911, Heike Kamerlingh Onnes found that at 4.2 kelvin the resistance in a solid mercury wire immersed in liquid helium suddenly vanished. He immediately realized the significance of the discovery. 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".
Heike Kamerlingh Onnes in his lab