Figure 4
From: Conventional empirical law reverses in the phase transitions of 122-type iron-based superconductors
The correlation between the ionic radius for AFe2As2 (A = Ca, Sr, Eu and Ba) iron arsenide superconductors and their corresponding transition pressure of T → cT phases (at ambient temperature).
The transition pressures (T → cT) in AFe2As2 show a correlation with the size of the ionic radius under ambient conditions, in which compounds exhibited higher transition pressure with larger cation ionic radius. The pressure-induced structural phase transitions for AFe2As2 were taken from reference 22, 25 and 28 along with this work. The dotted lines are meant to guide the eyes. The inset shows the ionic radius as a function of phase transition pressure for AEMO and AEMF2 (AEM = Ca, Sr and Ba). The data refer to reference 1–7.
