Wang Y F, Shao Y C, Hsieh S H, Chang Y K, Yeh P H, Hsueh H C, Chiou J W, Wang H T, Ray S C, Tsai H M, Pao C W, Chen C H, Lin H J, Lee J F, Wu C T, Wu J J, Chang Y M, Asokan K, Chae K H, Ohigashi T, Takagi Y, Yokoyama T, Kosugi N, Pong W F
Department of Physics, Tamkang University, Tamsui, 251, Taiwan.
Department of Applied Physics, National University of Kaohsiung, Kaohsiung, 811, Taiwan.
Sci Rep. 2018 May 17;8(1):7758. doi: 10.1038/s41598-018-25948-x.
Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.
通过温和的碳离子注入方法，利用各种基于同步辐射的光谱和显微镜技术来阐明碳掺杂氧化锌纳米线（ZnO-C:NW）的室温铁磁性。光致发光和磁滞回线表明，碳的注入减少了本征表面缺陷的数量，并增加了ZnO-NW的饱和磁化强度。X射线吸收光谱研究证实，间隙注入的碳离子构成了ZnO-C:NW中缺陷的主体。O和C K边的X射线磁圆二色光谱分别表明，ZnO-C:NW表面区域中未配对/悬空的O 2p键数量减少，且注入的碳离子的C 2p衍生态强烈影响ZnO-C:NW表面和体区域的净自旋极化。此外，这些发现与表面和体区域中碳注入ZnO的第一性原理计算结果非常吻合，该计算突出了注入碳分别在表面区域和体相中抑制和增强ZnO-C:NW铁磁性的稳定性。
