Figure 4. Magnetization, electrical resistance, and heat capacity of nominal Ba_0.8Fe₂Se₂.

(a) The magnetization of nominal Ba_0.8Fe₂Se₂ as a function of temperature. The left inset shows the magnetic hysteresises of nominal Ba_0.8Fe₂Se₂ measured at 10 K and 60 K in the range −25 kOe < H < 25 kOe, respectively. The right inset shows the temperature dependence of the electrical resistance of cold-pressed powder Ba_0.8Fe₂Se₂. (b) Low temperature heat capacity of cold-pressed powder Ba_0.8Fe₂Se₂. The red dotted line is the curve fitting of phonon contribution to the heat capacity.