Before revision: In 1986, Karl Müller and Johannes Bednorz discovered the first high temperature superconductor, a material which was superconducting at temperatures as high as 50 kelvins .
After revision: In 1986, Karl Müller and Johannes Bednorz discovered the first high temperature superconductor, La2-xBaxCuO4, which is superconducting at temperatures as high as 39 kelvin .