*2.4. Characterizations of MIOs and MNs*

The morphology of MIOs are analyzed by field emission scanning electron microscope (JEOL Ltd., Tokyo, Japan), and MIOs were dried up on silicon wafers. The wafers were anchored to SEM specimen mounts using double-sided carbon tape, and sputter deposited with platinum in 10 mA for 120 s. An X-ray diffractometer (D8 Advance X-ray Diffractometer, Bruker, Billerica, MA, USA) was used for identification of crystal dimensions. A thermogravimetric analyzer (Seiko Instruments Inc., Tokyo, Japan) provided a proportion of each compositions based on differential melting temperature with physical and chemical properties. Dynamics laser scattering (DLS) analysis, by using a particle sizer (Nano-ZS, Malvern, Worcestershire, UK), determined the average size and size distribution of MIOs diluted with deionized water. Field-dependent magnetization curves were evaluated by a superconducting quantum interference device (San Diego, CA, USA) from −10,000 to 10,000 Oe.
