(a)
(b)
(c)
(d)
Figure 5: AC minor hysteresis loops of liquid, fixed, and cellular samples. The amplitude of the AC magnetic field was (a, c) 4 kA/m or (b, d) 8 kA/m. The frequency was 400 kHz. Magnified images of (a) and (b) are shown in (c) and (d), respectively.