ABSTRACT:
Nano-powder and thin film samples of cadmium oxide doped with Al-Co ions were synthesised by sol-gel technique using a mixture of complexes of cadmium acetate dihydrate, Cobalt acetyl acetonate, and aluminum nitrate nonahydrate. The mass ratios of Al/Cd and Co/Cd in the investigated samples (CdO:Al, CdO:Co, and CdO:Al;Co) were 0.5% and 1%, respectively. The X-ray diffraction (XRD) study confirmed the formation of single-phase crystalline structures, thus, both Al and Co ions were successfully incorporated into CdO lattice. The purpose of the present study is to synthesise and investigate the possibility of creation of room-temperature ferromagnetic (RT-FM) properties in host CdO for diluted magnetic semiconductor (DMS) applications. Annealing in H2 atmosphere under certain conditions was used extensively to enhance the Heisenberg interactions between spins of the incorporated dopant ions and, thus boosted the created FM behaviour. Optical measurements revealed red shift of the bandgap by doping as well as hydrogenation. Magnetic measurements at RT disclosed various magnetic properties (DM, PM, and FM) at RT depending on the dopant type. However, with the hydrogenation, the magnetic behaviours of all investigated samples were converted to FM style. It was established that the saturation magnetisation of CdO:Al:Co nano-powder was greatly enhanced by ~ 400 times with the hydrogenation. Thus, it was proved the possibility of synthesis of doped CdO powders by sol-gel technique with tailored magnetic properties. Therefore, system of Al/Co-doped CdO nanopowders, owning these amazingly tunable magnetic manners, can be considered as a potential candidate for many applications such as DMS in addition to its usual TCO properties.