Structural, optical, and magnetic properties of Cu- and Ni-codoped CdO dilute magnetic nanocrystalline semiconductor: effect of hydrogen post-treatment

摘要

Cadmium oxide codoped with Cu and Ni ions powders was synthesised by thermal co-decomposition of a mixture of cadmium, copper, and nickel acetylacetonates. The mass ratio of Cu/Cd was fixed, while the Ni/Cd mass ratio was varied systematically. The purpose of the present study is to prepare powders having room-temperature ferromagnetic (RT-FM) properties. X-ray fluorescence (XRF) and X-ray diffraction (XRD) confirm the purity and the formation of single nanocrystalline structure of the as-prepared powders. The energy bandgap of the as-prepared powders was found to vary slightly and then increases by 3.96-38.02 % after post-H_2-treatment. Magnetic measurements reveal that all as-prepared doped CdO powders gained partial (RT-FM) properties. Furthermore, the created RT-FM is dependent on the Ni% doping level. After annealing under H_2 gas, a strong enhancement of RT-FM was observed, especially for 1.2 % Ni-doping-level powder where the whole powder became ferromagnetic with co-ercivity, remanence, and saturation magnetisation of 249.2 Oe, 4.52 memu/g, and 14.57 memu/g, respectively, representing an increase by ～241.3, 1062, and 1700 %, respectively, in comparison with the as-prepared sample. Thus, it was proved, for the first time, the possibility of producing of codoped CdO with RT-FM, where the magnetic characteristics can be tailored by doping and post-treatment under H_2 atmosphere, thus a new potential candidate for dilute magnetic semiconductor (DMS).