Critical Field
The upper critical field (UCF) is the magnetic field (usually expressed in teslas (T)) which completely suppresses superconductivity in a Type II superconductor at 0K (absolute zero).
More properly, the UCF is a function of temperature (and pressure) and if these are not specified absolute zero and standard pressure are implied.
Werthamer–Helfand–Hohenberg theory predicts the upper critical field (Hc2) at 0 K from Tc and the slope of Hc2 at Tc.
The UCF (at 0 K) can also be estimated from the coherence length(ξ) using the Ginzburg-Landau expression : Hc2 = 2.07 x 10-15 Tm2/(2 Pi ξ2)
Articles on superconductivity use Hc2 or Bc2 interchangeably since the materials are rarely magnetic.
Read more about Critical Field: Lower Critical Field
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