He Zihao, Gao Xingyao, Zhang Di, Lu Ping, Wang Xuejing, Kalaswad Matias, Rutherford Bethany X, Wang Haiyan
School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907-2045, USA.
School of Materials Engineering, Purdue University, West Lafayette, IN 47907-2045, USA.
Nanoscale. 2021 Oct 14;13(39):16672-16679. doi: 10.1039/d1nr04975e.
Two-dimensional (2D) materials with robust ferromagnetic behavior have attracted great interest because of their potential applications in next-generation nanoelectronic devices. Aside from graphene and transition metal dichalcogenides, Bi-based layered oxide materials are a group of prospective candidates due to their superior room-temperature multiferroic response. Here, an ultrathin BiFeMnO layered supercell (BFMO322 LS) structure was deposited on an LaAlO (LAO) (001) substrate using pulsed laser deposition. Microstructural analysis suggests that a layered supercell (LS) structure consisting of two-layer-thick Bi-O slabs and two-layer-thick Mn/Fe-O octahedra slabs was formed on top of the pseudo-perovskite interlayer (IL). A robust saturation magnetization value of 129 and 96 emu cm is achieved in a 12.3 nm thick film in the in-plane (IP) and out-of-plane (OP) directions, respectively. The ferromagnetism, dielectric permittivity, and optical bandgap of the ultrathin BFMO films can be effectively tuned by thickness and morphology variation. In addition, the anisotropy of all ultrathin BFMO films switches from OP dominating to IP dominating as the thickness increases. This study demonstrates the ultrathin BFMO film with tunable multifunctionalities as a promising candidate for novel integrated spintronic devices.
具有强铁磁行为的二维（2D）材料因其在下一代纳米电子器件中的潜在应用而备受关注。除了石墨烯和过渡金属二卤化物之外，铋基层状氧化物材料由于其优异的室温多铁性响应而成为一类有前景的候选材料。在此，使用脉冲激光沉积在LaAlO（LAO）（001）衬底上沉积了超薄BiFeMnO层状超胞（BFMO322 LS）结构。微观结构分析表明，在准钙钛矿中间层（IL）之上形成了由两层厚的Bi-O板和两层厚的Mn/Fe-O八面体板组成的层状超胞（LS）结构。在12.3 nm厚的薄膜中，面内（IP）和面外（OP）方向分别实现了129和96 emu/cm的强饱和磁化强度值。超薄BFMO薄膜的铁磁性、介电常数和光学带隙可通过厚度和形貌变化有效调节。此外，随着厚度增加，所有超薄BFMO薄膜的各向异性从以OP为主转变为以IP为主。本研究证明了具有可调多功能性的超薄BFMO薄膜是新型集成自旋电子器件的有前景的候选材料。
