MBE Growth of MnBi-based Single Crystal and Superlattice Films and Its Characterization by Nonlinear Magneto-Optical Effect

MnBi基单晶和超晶格薄膜的MBE生长及其非线性磁光效应表征

• 批准号: 10450004
• 负责人: SAITO Katsuaki
• 金额: $ 8.19万
• 依托单位: TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450004/
• 关键词: MnBi; MnAs; MBE growth; buffer layer; magneto-optical effect; electron beam lithography; ocused ion beam fabrication; nonlinear magneto-optical effect; MnBi薄膜; Mn; Biシード膜; MBE法; エピタキシャル成長; 垂直磁化膜; 電子線リソグラフィ; パターンドディスク; 分子線エピタキシー法; 磁気光学; M

In this project we have finished following three major topics (1) Epitaxial growth of good quality thin films of manganese pnictides including MnBi by MBE technique (2) Establishment of nano-fabrication technology for magnetic materials (3) Observation of surface magnetic properties by nonlinear magneto-optical effectDetails of these topics are described as follows : (1) Epitaxial growth of manganese pnictides : MBE growth of MnAs on nano-structured GaAs substrate and MBE growth of GaAlAs doped with 7% Mn. MBE growth of MnBi on MgO (001) substrate was carried out using Cu or Au layers as a buffer. Eiptaxial growth was unsuccessful by this method. On the other hand, simultaneous evaporation of Mn and Bi fluxes on a seed layer prepared by sequential deposition of Mn and Bi lead to successful epitaxial growth with a streaky RHEED pattern. The obtained film showed a perpendicular anisotropy with a magnetic hysteresis loop of a good squareness. Magneto-optical studies were also carried out … More in this film. (2) Nano-fabrication of magnetic material Embedded arrays of submicron magnetic dots were fabricated by electron-beam lithography technique : Si substrate was patterned to make a dot-array of less than 0. 1μm in diameter by electron beam exposure and was etched by reactive ion etching (RIE) technique. Co metal was evaporated to fill the hole prepared by RIE process and polished to make a flat surface by CMP (chemical mechanical polishing) technique. Next, magnetic films (Co) were etched directly by focused ion beam (FIB) method to fabricate 0.1μm pattern. MFM observation showed snake pattern, the same as that of un-structured Co film, suggesting that the nano-structure made no significant effect on the anisotropy. (3) Nonlinear magneto-optical effect was observed in a few magnetic films. In Fe/Au magnetic superlattices, azimuthal angle dependence of nonlinear Kerr effect showed a well defined four-fold symmetry pattern similar to that observed in the azimuthal dependence of MSHG in the same superlattice. The result was successfully analyzed considering the symmetry properties of nonlinear susceptibility tensor.During the term of this project, these three experiments were carried out independently using the different materials. Fabrication of nano-structures as described in (2) using the epitaxial MnBi film prepared by the process (1) and observation of nonlinear magneto-optical effect by means of (3) on the same sample is a future problem. Less

本研究主要完成了以下三个方面的工作：（1）分子束外延技术外延生长高质量的磷锰氧化物薄膜（包括MnBi）（2）磁性材料纳米加工技术的建立（3）非线性磁光效应观察表面磁特性。纳米结构GaAs衬底上MnAs的分子束外延生长和掺7% Mn的GaAlAs的分子束外延生长。采用Cu或Au层作为缓冲层，在MgO（001）衬底上进行了MnBi的分子束外延生长。用这种方法不能成功地进行轴向生长。另一方面，Mn和Bi通量的同时蒸发通过顺序沉积Mn和Bi制备的种子层上导致成功的外延生长与条纹RHEED图案。所得薄膜表现出垂直各向异性，磁滞回线具有良好的矩形度。还进行了磁光研究 ...更多信息 在这部电影里(2)磁性材料的纳米加工利用电子束光刻技术制备了亚微米磁性点阵的镶嵌阵列：在硅衬底上构图，得到小于0。1μm的直径，并通过反应离子刻蚀（RIE）技术进行刻蚀。利用化学机械抛光（CMP）技术，将金属Co蒸发填充到RIE工艺制备的孔中，并进行抛光，得到平整的表面。然后，用聚焦离子束（FIB）方法直接刻蚀磁性薄膜（Co），制作出0.1μm的图形。MFM观察到与非结构化Co膜相同的蛇形图案，表明纳米结构对各向异性没有显著影响。(3)在少数磁性薄膜中观察到非线性磁光效应。在Fe/Au磁性超晶格中，非线性Kerr效应的方位角依赖性表现出一个明确的四重对称性模式，类似于在同一超晶格中观察到的MSHG方位角依赖性。在本项目期间，这三个实验分别采用不同的材料进行，实验结果与实验结果吻合较好。使用通过工艺（1）制备的外延MnBi膜制造如（2）中所述的纳米结构以及通过（3）在同一样品上观察非线性磁光效应是未来的问题。少

项目成果

T. Ishibashi, F. Minami, G. Kaise, J. Yamamoto, Y. Morishita, K. Sato: "Characterization of Embedded Submicron Co Structure"Pfoc. Int. Conf. Ferrites, Tokyo Sept. in press. (2000)

T. Ishibashi、F. Minami、G. Kaise、J. Yamamoto、Y. Morishita、K. Sato：“嵌入式亚微米钴结构的表征”Pfoc。

K.Sato,M.Miyamoto,A.Kodama,T.Takanashi,A.Petukhov and Th.Rasing: "Azimuth Angle Dependence of MSHG in Magnetic Superlattices and its Symmetry Analysis,(to be published) "Proc.Int.Conf.Ferrites, Kyoto,2000. (印刷中). (2000)

K. Sato、M. Miyamoto、A. Kodama、T. Takanashi、A. Petukhov 和 Th. Rasing：“磁超晶格中 MSHG 的方位角依赖性及其对称性分析，（即将出版）”Proc.Int.Conf。铁氧体，京都，2000 年（印刷中）。

K.Sato, S.Mitani, K.Takanashi, H.Fujimori, A.Kirilyuk, A.Petukhov, Th.Rasing: "Nonlinear magneto-optical effect in Fe/Au superlattices"J. Magn. Soc. Jpn.. 23,[1-2]. 352-353 (1999)

K.Sato、S.Mitani、K.Takanashi、H.Fujimori、A.Kirilyuk、A.Petukhov、Th.Rasing：“Fe/Au 超晶格中的非线性磁光效应”J。

G.A.Medvedkin, T.Ishibashi, T.Nishi, K.Sato: "New magnetic semiconductor Cd_<1-x>Mn_xGeP_2"Semiconductors. 35,[3]. 305-309 (2000)

G.A.Medvedkin、T.Ishibashi、T.Nishi、K.Sato：“新型磁性半导体Cd_<1-x>Mn_xGeP_2”半导体。

T.Ishibashi,F.Minami,G.Kaise,J.Yamamoto,Y.Morishita and K.Sato: "Characterization of Embedded Submicron Co Structure"Proc.Int.Conf.Ferrites, Tokyo Sept,2000. (印刷中). (2000)

T. Ishibashi、F. Minami、G. Kaise、J. Yamamoto、Y. Morishita 和 K. Sato：“嵌入式亚微米钴结构的表征”，东京铁氧体会议，2000 年 9 月。 (2000)