Regular Article

Effect of different Mn doping and point vacancy ratios on the magnetic properties of ZnO

¹ School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, P.R. China
² College of Science, Inner Mongolia University of Technology, Hohhot 010051, P.R. China
³ Key Laboratory of Thin Films and Coatings of Inner Mongolia Autonomous Region, Hohhot 010051, P.R. China

^* e-mail: by0501119@126.com

Received: 14 January 2021
Received in final form: 1 March 2021
Accepted: 6 April 2021
Published online: 19 May 2021

Abstract

The magnetic source of Mn doping and Zn vacancy coexisting in ZnO is controversial. To solve this problem, this work used the generalized gradient approximation first-principles plane-wave ultrasoft pseudo potential + U method based on density functional theory to calculate the effect of different Mn doping to point vacancy ratios on the magnetic properties of ZnO. The formation energy of ZnO with different Mn-substituted Zn (Mn_Zn) to oxygen/zinc vacancy (V_O/V_Zn) ratios can be smaller and more stable in zinc (Zn)-rich conditions than in oxygen (O)-rich conditions. The ZnO system exhibits p-type half-metallic ferromagnetism when the Mn_Zn to V_Zn ratio is 2:1 or 2:2. When the Mn doping amount is constant, the Zn vacancies increase and the total magnetic moment of the doped system decreases. For the ZnO system in which Mn doping and oxygen vacancies coexist, when the amount of oxygen vacancies is constant, with Mn doping increase, the magnetic moment becomes larger. Both Zn₂₂Mn₂O₂₂ and Zn₂₀Mn₂O₂₄ can achieve ferromagnetic characteristics above room temperature.