Historically, it was for a long time unclear whether a superconductor undergoes a first- or a second-order phase transition. The question was finally settled in 1982. If the Ginzburg–Landau parameter κ κ that distinguishes type-I and type-II superconductors (see also here) is large enough, vortex fluctuations become important which drive the transition to second order. The tricritical point lies at roughly κ κ = 0.76 / 2 , slightly below the value κ κ = 1 / 2 where type-I goes over into type-II superconductor. The prediction was confirmed in 2002 by Monte Carlo computer simulations.