Magnetic Phase Formation in Self-Assembled Epitaxial BiFeO3–MgO and BiFeO3–MgAl2O4 Nanocomposite Films Grown by Combinatorial Pulsed Laser Deposition

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• 作者：Dong Hun Kim ; XueYin Sun ; Tae Cheol Kim ; Yun Jae Eun ; Taeho Lee ; Sung Gyun Jeong ; Caroline A. Ross
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 3, 2016
• 年：2016
• 卷：8
• 期：4
• 页码：2673-2679
• 全文大小：595K
• ISSN：1944-8252

文摘

Self-assembled epitaxial BiFeO<sub>3sub>–MgO and BiFeO<sub>3sub>–MgAl<sub>2sub>O<sub>4sub> nanocomposite thin films were grown on SrTiO<sub>3sub> substrates by pulsed laser deposition. A two-phase columnar structure was observed for BiFeO<sub>3sub>–MgO codeposition within a small window of growth parameters, in which the pillars consisted of a magnetic spinel phase (Mg,Fe)<sub>3sub>O<sub>4sub> within a BiFeO<sub>3sub> matrix, similar to the growth of BiFeO<sub>3sub>–MgFe<sub>2sub>O<sub>4sub> nanocomposites reported elsewhere. Further, growth of a nanocomposite with BiFeO<sub>3sub>–(CoFe<sub>2sub>O<sub>4sub>/MgO/MgFe<sub>2sub>O<sub>4sub>), in which the minority phase was grown from three different targets, gave spinel pillars with a uniform (Mg,Fe,Co)<sub>3sub>O<sub>4sub> composition due to interdiffusion during growth, with a bifurcated shape from the merger of neighboring pillars. BiFeO<sub>3sub>–MgAl<sub>2sub>O<sub>4sub> did not form a well-defined vertical nanocomposite in spite of having lower lattice mismatch, but instead formed a two-phase film with in which the spinel phase contained Fe. These results illustrate the redistribution of Fe between the oxide phases during oxide codeposition to form a ferrimagnetic phase from antiferromagnetic or nonmagnetic targets.