Effect of high magnetic field on magnetic properties of oxidized ZnO:Co film prepared with different growth models

Growth models and high magnetic field (HMF) are employed to affect diluted magnetic performance of Co-doped ZnO (ZnO:Co) films which oxidize Co-Zn evaporated films at 300 °C for 120 min in open air. Nanograined boundaries and dense structure obtained in the co-deposition films are helpful to present a better diluted magnetic performance. Two phases of Zn and ZnO coexist in the films at a low oxidation temperature. Both the bilayer Co/Zn film and the application of HMF during the oxidation process offer an easy way to increase oxygen vacancies, which are inconducive to improve the ferromagnetism. The co-deposition 0 T film has the best diluted magnetic performance compared with the bilayer 0 T film. To be specific, saturation magnetization MS of the co-deposition 0 T film (100.1 emu/cm3) increases by 190%, squareness S increases from 0.31 to 0.75 and coercivity HC increases from 34.6 Oe to 183.5 Oe. With the application of HMF, the MS of the co-deposition films decreases by 44% to approximately 55.8 emu/cm3 and the HC increases to 118.4 Oe.