*3.3. Magnetic Property*

The magnetic characteristics of the CI particles of the MREs play an important role in their MR properties [116,117]. Knowing the magnetization information of the magnetic particles provides important information for applying the magnetic particles to the MRE. This magnetization investigation is obtained in the form of hysteresis loops as a graph of magnetization value versus magnetic field strength. Figure 6a shows the magnetization curves of pristine CI particles and particles covered with PGMA on the CI surface [60]. Since CI particles are soft magnetics, they show narrow magnetic hysteresis loops. For pure CI, saturation magnetization was 198 Am<sup>2</sup>/kg and CI/PGMA was 153 Am<sup>2</sup>/kg, respectively, confirming that the saturation magnetization is reduced by the coating of PGMA. Figure 6b is the magnetization curve of CI particles coated with poly(trimethylsilyloxyethyl methacrylate) (PHEMATMS) [118]. It indicated that the saturation magnetization value decreased as the PHEMATMS coating thickness increased from 11 nm to 22 nm.

**Figure 6.** (**a**) VSM curves of pure CI (open dark square) particles and PGMA coated CI (open blue circle) particles [60] and (**b**) magnetization curves of a—bare CI, b—CI-g-PHEMATMS-1 (11 nm), and c—CI-g-PHEMATMS-2 (22 nm) particles obtained via VSM [118].
