Published 07 February, 2020; last updated 28 May, 2020
The maximum superconducting temperature of any material up to 1993 contained four greater than 10-year discontinuities: A 14-year discontinuity with NbN in 1941, a 26-year discontinuity with LaBaCuO4 in 1986, a 140-year discontinuity with YBa2Cu3O7 in 1987, and a 10-year discontinuity with BiCaSrCu2O9 in 1987.
YBa2Cu3O7 superconductors seem to correspond to a marked change in the rate of progress of maximum superconducting temperature, from a rate of progress of .41 Kelvin per year to a rate of 5.7 Kelvin per year.
This case study is part of AI Impacts’ discontinuous progress investigation.
Superconductors were discovered in 1911.1 Until 1986 the maximum temperature for superconducting behavior had gradually risen from around 4K to less than 30K (see figure 2 below). Theory at the time apparently predicted that 30K was an upper limit.2 In 1986 a new class of ceramics known as YBCO superconductors was discovered to allow superconducting behavior at higher temperatures: above 80K,3 and within seven years, above 130K.4
We looked at data for the maximum temperature at which any material is known to have superconducting behavior.
We found the following data in a figure from the University of Cambridge’s online learning materials course, DoITPoMS,6 and have verified most of it against other data sources (see our spreadsheet, where we also collected ‘Extended data’ to verify that these were indeed the record temperatures).
We display the original figure from DoITPoMS in Figure 2 below, followed by our figure, Figure 3, which includes the a more recent superconducting material, H2S.
We modeled this data as linear within two different regimes, one up to LaBaCu04 in 1986, and another starting with 1986 until our last data point.8 Using previous rates from those trends, we calculated four greater than 10-year discontinuities (rounded), shown in the table below:9
We note that there was a marked change in the rate of progress of maximum superconducting temperature with YBa2Cu3O7. The maximum superconducting temperature changed from a rate of progress of .41 Kelvin per year to a rate of 5.7 Kelvin per year.11