Abstract
Control over the magnetic interactions in dilute magnetic semiconductor quantum dots (DMSQDs) is a key issue to future development of nanometer-sized integrated "spintronic" devices. However, manipulating the magnetic coupling between impurity ions in DMSQDs remains a great challenge because of the intrinsic quantum confinement effects and self-purification of the quantum dots. Here, we propose a hybrid structure to achieve room-temperature ferromagnetic interactions in DMSQDs, via engineering the density and nature of the energy states at the Fermi level. This idea has been applied to Co-doped ZnO DMSQDs where the growth of a reduced graphene oxide shell around the Zn0.98Co0.02O core turns the magnetic interactions from paramagnetic to ferromagnetic at room temperature, due to the hybridization of 2pz orbitals of graphene and 3d obitals of Co2+-oxygen-vacancy complexes. This design may open up a kind of possibility for manipulating the magnetism of doped oxide nanostructures.
Original language | English (US) |
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Pages (from-to) | 10589-10596 |
Number of pages | 8 |
Journal | ACS Nano |
Volume | 8 |
Issue number | 10 |
DOIs | |
State | Published - Oct 28 2014 |
Bibliographical note
Publisher Copyright:© 2014 American Chemical Society.
Keywords
- Co-doped ZnO QDs
- ferromagnetic exchange
- RGO
- XAFS
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy