Growth of high-quality thin films of the novel ZnAs-based magnetic semiconductors and improving the properties

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H02921
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Nagoya University
• Principal Investigator: Ikuta Hiroshi 名古屋大学, 工学研究科, 教授 (30231129)
• Co-Investigator(Kenkyū-buntansha): 畑野 敬史 名古屋大学, 工学研究科, 助教 (00590069)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 磁性半導体 / 砒化亜鉛化合物 / 薄膜成長 / 電子構造制御

Outline of Final Research Achievements

We studied thin film growth of BaZn2As2, the mother compound of novel dilute magnetic semiconductors that are drawing considerable attention in recent years. The thin film growth of this compound had been possible only by a complex, five-step process until the start of the present study, while we have established a simple one-step growth method by means of molecular beam epitaxy. Thin films in which Fe was partially substituted for Zn were also grown. Transport measurements revealed that the partially Fe substituted films are n-type semiconductors, and the energy gap decreased with Fe content. The magnetization measurements showed that the Fe substituted films exhibit ferromagnetic behavior. Single crystals of compounds in which As was replaced by Sb or P were also grown, and the physical properties were studied. In particular, we observed a ferromagnetic behavior at room temperature for the Sb-based compound.

Free Research Field

固体物性、応用物性、薄膜成長

Academic Significance and Societal Importance of the Research Achievements

現代の情報化社会を支える電子素子のさらなる高性能化を目指したスピントロニクス研究が精力的に進められている。特に、室温以上で強磁性を示す優れた磁性半導体が開発されれば、既存の半導体技術と親和性の高い新規デバイスの開発につながると期待される。近年、BaZn2As2を母相とする新たな磁性半導体が相次いで報告され注目されている。薄膜はデバイス応用にも、また基礎物理解明にも重要である。本研究では、この系のエピタキシャル薄膜を成長する手法を確立した。また、Znの一部をFeに置換した薄膜も成長し、強磁性的振舞いを観測した。さらには関連物質の物性測定により、これらの系に関する様々な知見が得られた。