A Study On Magnetic Properties Of ZnO

The magnetic properties of non-transition metals (C and N) doped ZnO were investigatedby using the first principle method based on density functional theory.For C doped ZnO system, the system can produce spontaneous spin polarzation when wereplaced one O atom with one C atom of ZnO. The system exhibitied FM stability when wereplaced two O atoms with two C atoms. The origin of FM can be explained by coupingbetween C energy levels. In addition, we can find that C atoms in ZnO have a clear clusteringtendency and C atoms in ZnO may produce long-range FM couping interactions. Becausecomplexity of the hybridization and anisotropy of spin density distributed in space, the FMcoupling can be tuned by axis and shear strain.For N doped ZnO system, we investigate the magnetic properties of N doped ZnO crystal.Firstly, we analyzed FM coupling in N doped ZnO. The results indicated that the systemexhibitied FM stability. Secondly, we calculated the defect formation and inoization energies ofsystem. The results indicated that oxygen vacancies easily form under zinc-rich limit and zincvacancies easily form under oxygen-rich limit. Finally, we investigated defect and strainaffecting magnetic properties of N doped ZnO.We also investigate the magnetic properties of N doped ZnO thin films. Firstly, weinvestigate spin polarzation of system. Secondly, we analyzed the origin of FM in system.Finally, we analyzed the Magnetic exchange coefficient and Curie transition temperature byusing the local Heisenberg electronic model. The results showed that the film exhibited weakferromagnetic characteristics.