Ferromagnetism induced by Zn vacancy defect and lattice distortion in ZnO

Abstract

Through the full potential linearized augmented plane wave method, we have explored the vacancy defect induced magnetism in wurtize ZnO. It has been found that the Zn vacancy defect brings a spin polarized state in the nearest neighbor oxygen atoms, whereas the oxygen vacancy defect has no influence on the magnetism. However, it is found that the lattice distortion is a crucial factor for the Zn vacancy induced ferromagnetism because the ferromagnetic ground state cannot be achieved if there is no lattice distortion due to Zn vacancy defect. The magnetic moment of oxygen atom in the nearest neighbor from the Zn vacancy site is ranged from 0.10 to 0.19 μB and the spin polarized oxygen atoms have metallic feature in both spin states. These results are quite different from those found in other calculation [Q. Wang et al., Phys. Rev. B 77, 205411 (2008)]. In addition, we have found that the ferromagnetic exchange interaction among oxygen atoms is mediated by Zn 3d state. Along with these, the theoretically calculated x-ray absorption spectroscopy and x-ray magnetic circular dichroism are presented.

Defect-induced magnetism in undoped wide band gap oxides: Zinc vacancies in ZnO as an example

“…61 The other evidence comes from the recent reports where cation vacancies was suggested to be responsible in establishing the ferromagnetism in wide band gap oxides, 5,31,40,73 Additionally, many recent theoretical calculations suggest that the s electrons contributed by V O cannot establish ferromagnetism. 27,34 These considerations guided us to focus on the role of V Zn in the first-principles calculations which will be detailed in the next section.…”

Structural, optical, XPS and magnetic properties of Zn particles capped by ZnO nanoparticles

“…The existance of RFTM in the undoped ZnO stimulated discussion about the role of intrinsic defects in this phenomenon. For the Zn-O system, also known as a pristine oxide, it was shown that defects, such as Zn and O vacancies [16][17][18][19][20][21], Zn interstitials [22], grain boundaries [23] and lattice distortions [24], might contribute to the development of RTFM. If all these defects are indeed responsible for the ferromagnetism in thin films and nanoparticles, they should be thermodynamically stable at least to room temperature, and magnetic exchange interaction between them should be strong enough for the existence of ferromagnetism to be feasible [25].…”

Defects induced ferromagnetism in Mn doped ZnO

“…It is also found that the defect species involved in inducing ferromagnetism in one ZnO based DMS system may not be effective in similar others [4,7,20]. The site occupied by the dopant atom [16], its size, electronic configuration and defect decoration [9], lattice strain [21], band gap [5] etc. determines the final and modified band structure of the ZnO host lattice.…”