[19p-234B-1~19] 6.4 薄膜新材料

▲ [19p-234B-2] Preparation of RFe₂O₄ (R = Lu, Tm) Thin Films by Pulsed Laser Deposition Method and Their Magnetic Properties

〇(D)YouJin Kim¹、Shinya Konishi¹、Yuichiro Hayasaka²、Katsuhisa Tanaka¹ (1.Graduate school of engineering, Kyoto Univ.、2.The electron microscopy center for Tohoku Univ.)

キーワード：multiferroic, thin film, interface structure

In this study, we successfully prepared RFe₂O₄ (R = Lu, Tm) thin films epitaxially grown on yttria-stabilized zirconia (YSZ, ZrO₂ stabilized with 10 mol% Y₂O₃) (111) substrate, as demonstrated by X-ray diffraction patterns illustrated in Fig.1. Although there are several reports on the synthesis of LuFe₂O₄ epitaxial thin film[2]^,[3], this is the first report on the fabrication of epitaxial TmFe₂O₄ thin film to the best of our knowledge. Also, we observed interesting structure of LuFe₂O₄ thin film by utilizing HAADF-STEM measurements. At the interface between the substrate and the thin film, two atomic layers of hexagonal-LuFeO₃, and Lu₂Fe₃O₇ phases are formed, and above these layers LuFe₂O₄ thin film is grown. Temperature and magnetic field dependence of magnetization was explored by using SQUID. The temperature dependence of magnetization seems to show that the magnetization takes non-zero value even above room temperature in contrast to the bulk single-crystalline phase. The result may be related to the higher magnetic phase transition temperature observed for (LuFeO₃)_n-(LuFe₂O₄)_m superlattice.
[1] Julia. A. Mundy et al., Nature 537, 523-527 (2016).
[2] Wang. A. et al., Phys. Rev. B. 85, 155411 (2012).
[3] Fujiwara. K. et al., J. Phys. D: Appl. Phys. 46, 155108 (2013).