  The magnetic transition-metal (TM) @ oxide nanoparticles have been of great
interest due to their wide range of applications, from medical sensors in
magnetic resonance imaging to photo-catalysis. Although several studies on
small clusters of TM@oxide have been reported, the understanding of the
physical electronic properties of TMn@(ZnO)42 is far from sufficient. In this
work, the electronic, magnetic and optical properties of TMn@(ZnO)42 (TM = Fe,
Co and Ni) hetero-nanostructure are investigated using the density functional
theory (DFT). It has been found that the core-shell nanostructure Fe13@(ZnO)42,
Co15@(ZnO)42 and Ni15@(ZnO)42 are the most stable structures. Moreover, it is
also predicted that the variation of the magnetic moment and magnetism of Fe,
Co and Ni in TMn@ZnO42 hetero-nanostructure mainly stems from effective
hybridization between core TM-3d orbitals and shell O-2p orbitals, and a
magnetic moment inversion for Fe15@(ZnO)42 is investigated. Finally, optical
properties studied by calculations show a red shift phenomenon in the
absorption spectrum compared with the case of (ZnO)48.
