Figure 1
From: Emergence of Multiple Superconducting Phases in (NH3)yMxFeSe (M: Na and Li)
M / H vs. T plots of (a) (NH3)yNa0.1FeSe (low-Tc phase) and(b) (NH3)yNa1.0FeSe (high-Tc phase) in ZFC and FC modes (H = 20 Oe). Insets in (a) and (b) show the method used to determine Tc. XRD patterns of (c) (NH3)yNa0.2FeSe (low-Tc phase) and (d) (NH3)yNa1.0FeSe (high-Tc phase); ‘x’ marks correspond to the experimental XRD patterns. Red and green lines refer to calculated patterns (LeBail fitting) and background, respectively. Ticks refer to the peak positions predicted. In (c), two phases ((NH3)yNa0.2FeSe and β-FeSe) are used in LeBail fitting, while in (d), a single phase ((NH3)yNa1.0FeSe) is used.
