Influences of the type of dopant and substrate on ferromagnetism in ZnO:Mn

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• 作者：Kongping Wu ; Jianhui Jiang ; Kun Tang ; Shulin Gu ; Ji ; ong Ye ; Shunming Zhu ; Kailin Lu ; Mengran Zhou ; Mingxiang Xu ; Rong Zhang ; Youdou Zheng
• 关键词：Dilute magnetic semiconductor ; ZnO template ; Magnetization ; First principle ; ZnO ; Mn ; Ferromagnetism
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：April, 2014
• 年：2014
• 卷：355
• 期：Complete
• 页码：51-57
• 全文大小：1392 K

文摘

ZnO:Mn films doped with indium (In) and nitrogen (N) have been grown on sapphire and ZnO template substrates, respectively by the metal-organic chemical vapor deposition method. All these samples show clear hysteresis loops and saturation magnetizations (M_S) at room temperature characterized by a vibrating sample magnetometer in a Quantum Design Physical Property Measurement System. For the n-type ZnO:(Mn, In) and ZnO:Mn samples, the mechanism of the room-temperature ferromagnetism (RTFM) has been ascribed to the interactions between BMPs, which are formed by the magnetic coupling between Mn ions and the oxygen vacancies (V_O) defects. However, for the p-type ZnO:(Mn, N) samples, a single mechanism is not fully responsible for the measured RTFM. In contrast with the role of V_O in ZnO:(Mn, In) and ZnO:Mn system, the incorporation of V_O in ZnO:(Mn, N) would weaken the FM. For the ZnO:(Mn,N), the observed highest M_S is mainly ascribed to the RKKY interactions from the N 2p and Mn 3d ferromagnetic exchange coupling. Besides, a density functional theory simulation also indicates that ferromagnetic coupling may be enhanced by V_O in n-type ZnO:(Mn, In) and ZnO:Mn films, while the V_O defects in p-type ZnO:(Mn:N) films act oppositely, that may weaken the ferromagnetic coupling.