Zeng Ze-Ting, Jiang Feng-Xian, Ji Li-Fei, Zheng Hai-Yun, Zhou Guo-Wei, Xu Xiao-Hong
School of Chemistry and Materials Science of Shanxi Normal University, Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education Linfen 041004 China
Research Institute of Materials Science of Shanxi Normal University, Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Techonology Linfen 041004 China.
RSC Adv. 2018 Sep 6;8(55):31382-31387. doi: 10.1039/c8ra06343e. eCollection 2018 Sep 5.
Transition metal doped TiO diluted magnetic semiconductors have attracted considerable interest due to their room temperature ferromagnetism. However, most TiO films are highly insulating, and thus the magnetic properties can not be controlled by tuning the carrier concentration. This will limit their application in controlling magnetization electrical gating. Here, we deposit rutile Ti V O ( = 0.03 and 0.05) films with the thickness between 30 and 245 nm by the pulsed laser deposition technique, and observe an obvious room temperature ferromagnetic behavior in all films. The high resolution X-ray photoelectron spectroscopy results indicate that V substituting Ti ions in the TiO lattice, with the +3 valence state having two unpaired d electrons, is responsible for the local spin. More importantly, the systemic investigations of transport properties for Ti V O films reveal that the films are n-type and have metallic conductivity with a carrier density of about 10/cm. Further studies suggest that the oxygen vacancies play a dual role of contributing to the metallic conductivity of the Ti V O films, and also providing the free electrons to mediate the long-range ferromagnetic coupling between two magnetic polarons. These findings may offer promise for gate-tunable ferromagnetism in future semiconductor spintronics.
过渡金属掺杂的TiO稀释磁性半导体因其室温铁磁性而引起了广泛关注。然而，大多数TiO薄膜具有高度绝缘性，因此其磁性无法通过调节载流子浓度来控制。这将限制它们在控制磁化电门控方面的应用。在此，我们通过脉冲激光沉积技术制备了厚度在30至245纳米之间的金红石型TiV O（ = 0.03和0.05）薄膜，并在所有薄膜中观察到明显的室温铁磁行为。高分辨率X射线光电子能谱结果表明，V在TiO晶格中取代Ti离子，+3价态有两个未配对的d电子，是产生局部自旋的原因。更重要的是，对TiV O薄膜输运性质的系统研究表明，这些薄膜是n型的，具有金属导电性，载流子密度约为10/cm。进一步的研究表明，氧空位起到了双重作用，既有助于TiV O薄膜的金属导电性，又提供自由电子来介导两个磁极化子之间的长程铁磁耦合。这些发现可能为未来半导体自旋电子学中的门控可调铁磁性带来希望。
