Effects of Co doping and O vacancy on the magnetism of ZnO. (February 2020)

• Record Type: Journal Article
• Authors: Hou, Qingyu; Liu, Yajing; Li, Wenling
• Is Part Of: Solid state communications. Volume 306(2020)
• Publication Date: 2020-02
• Subjects: Co doping and O vacancy -- ZnO -- Magnetism -- First-principles; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2019.113775
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: Existing defect models for Co-doped ZnO with O vacancy ( V O ) are controversial in explaining the origin of the magnetism. To address this issue, we investigated the effects of Co doping and V O on the magnetic properties of ZnO through first-principles calculations by using generalized gradient approximation + U under the density functional theory. The total density of states of co-doping of one Co and one V O shows half-metallic behavior, which is highly beneficial when using dilute magnetic semiconductors (DMSs) as a hole injection source. The ferromagnetism for co-doping of one Co and one V O is derived from the double exchange effects among the spin polarized electrons of O–2p, Co–3d, and Zn–4s states as mediated by the electron carriers from V O, which is consistent with the mean field approximation theory and the double exchange mechanism theory. The co-doping of two Co and two V O causes the ZnO crystal undergo transition from anti-ferromagnetism (AFM) to ferromagnetism (FM) with the change of Co–Co distance. Zn34 Co2 O35 d (the Co–Co distance is 6.136 Å) can achieve Curie temperature higher than room temperature. In the same doping mode, increased concentrations of Co and V O increase the net magnetic moments. Highlights: Co-doped ZnO with O vacancy shows half-metallic behavior of which is highly beneficial for DMSs as a hole injection source. The origin of ferromagnetic of Co-doped ZnO with O vacancy was mediated by the electron carriers from V O . Zn34 Co2 O35 undergo transition from AFM to FM with the change of Co–Co distance. Zn34 Co2 O35 d (the Co–Co distance is 6.136 Å) can achieve Curie temperature higher than room temperature. Increased concentrations of Co to V O induces more net magnetic moments.