Ferromagnetism in Nanostructured TiO2/Al System Due to Surface Charge Transfer
详细信息 查看全文
- 作者：Zhiqiang Jiang ; Shijian Chen ; Dingke Zhang
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：February 20, 2014
- 年：2014
- 卷：118
- 期：7
- 页码：3789-3794
- 全文大小：354K
- ISSN：1932-7455
文摘
Ferromagnetism has been induced in nanostructured TiO2/Al powders prepared by ball milling at room temperature. This study presents the investigation of the origin of the magnetism in a TiO2/Al system with a combination of experiments and density functional theory (DFT) simulations. Our results demonstrate that adsorption of Al on surfaces of TiO2 nanostructures yields spontaneous magnetization. Our DFT simulations show that spin-polarized charge-transfer occurs from an adsorbed Al atom to O 2p state in surface and subsurface for some unique configurations. X-ray absorption near edge structure (XANES) spectra of the magnetic nanostructured TiO2/Al provide the necessary experimental evidence of the charge transfer and confirm the origin of ferromagnetic behavior. On the basis of the experiments and DFT simulations, we believe the room temperature ferromagnetism in nanostructured TiO2/Al originates from charge-transfer from Al to O atoms. Our results illustrate a complex interplay between the atomic level interfacial structure and the resulting ferromagnetic ordering in metal-coated semiconductor oxide nanostructures.