135708.fig.001a
(a)
135708.fig.001b
(b)
Figure 1: (a) Néel rotation of magnetization inside a fixed magnetic particle due to the spontaneously reversing the magnetization from one easy direction to the other (the particle does not rotate); (b) Brownian rotation of an MNP due to the rotation of the torque generated by the interaction of the magnetic field with the magnetization (the particle rotates as a whole) [17].