“…As shown in Figure 4, the XRD pattern indicates that these Figure 3d, and the latter seven are very near to those for standard Fe 3 O 4 : 2.966, 2.53, 2.096, 1.712, 1.614, 1.483, and 1.279 Å. [41] Although small traces of maghemite or hematite cannot be totally ruled out by the XRD, SAED, or HRTEM characterization, these results identify that the iron oxide NPs are mostly of the magnetite cubic spinel phase. The size, calculated by the Sherra equation [42] from the identified XRD peaks, is 9.4 Ϯ 2.4 nm, almost the same as that observed from the TEM images.…”