[P-29] Realization of high quality Fe3O4 thin film on atomically flat and high crystallinity MgO substrate surface 〇Ai Isohashi Osaka1, Daisetsu Toh1, Kazuto Yamauchi1, Yasuhisa Sano1, Hidekazu Tanaka1, Azusa Nakamoto Hattori1 (1.Osaka University) Keywords:Surface treatment、Chemical polishing、Film device、Strongly correlated electron system、