Physicochemical, structural and induced ferromagnetic properties of Co–In-codoped CdO synthesised via Cd chloride: significant effect of post-treatment hydrogen

Nanoparticle solid solution powders of cadmium oxide doped with different concentrations of cobalt and indium ions were synthesised by solvothermal method through CdCl 2 ⋅ H 2 O precursor route. The objective of the present work is to study and develop conditions necessary to create stable room-temperature ferromagnets (RT-FMs) in transparent conducting oxide (TCO) CdO for applications in the field of dilute magnetic semiconductors (DMSs). To achieve this aim, cobalt (Co 2+ ) dopant ions were used as a source of stable FM, while In 3+ dopant ions supply free electrons that enhance the electronic medium of interaction. The electronic medium in the host CdO lattice, which carries the long-range spin–spin (S.S) exchange interaction between localised Co 2+ (3d) spins of dopant ions, was further developed by annealing in hydrogen gas (hydrogenation). The crystalline structure of the powder samples was investigated by the X-ray diffraction (XRD) method. The optical absorption properties were studied by diffuse reflection spectroscopy (DRS). Magnetic measurements reveal that the Co–In-codoped CdO powder has FM properties superimposed on paramagnetic (PM) behaviour. However, annealing in hydrogen atmosphere strongly boosts the created FM so that the saturation magnetisation increases ∼90 times. Physical explanations and discussion are given in the article. Thus, it is proved that the magnetic properties could be tailored to TCO CdO by Co-doping and post-treatment under H 2 atmosphere.