Figure 2

(a) Magnetization versus field (M-H) curve at 1.8 K with a field sweep rate of 25 Oe/s for the Sr₂CoO₄. (b) dM/dH-H curve at 1.8 K for the Sr₂CoO₄. The inset of (a) shows the three measurement runs of the same piece of sample obtained under the same measurement condition.