Controlled growth of hexagonal nanocrystals Co and Gd co-doping ZnO by hydrothermal method

The control of nanostructured zinc oxide (ZnO) materials is essential for the development of smart and functional nanoscale devices. Using controlled hydrothermal growth conditions, cobalt (Co)- and gadolinium (Gd)-co-doped zinc oxide hexagonal nanocrystals were synthesized at a low temperature (70°C). The role of hexamethylenetetramine (HMTA; C₆H₁₂N₄) in engineering pure and doped zinc oxide morphology was examined. The results indicated that the hexagonal plates are transformed into a hexagonal flowerlike structure by changing the molar ratio of HMTA/precursors. The possible growth mechanism of the formation of hexagonal nanocrystals (hexagonal plates and nanoflowerlike structure) is discussed. The magnetic properties exhibited enhanced ferromagnetism after the incorporation of gadolinium into the zinc oxide matrix. An enhancement in saturation magnetization is discussed mainly in correlation with the strain effect. These doped zinc oxide nanostructures are expected to drive improvements mainly in the performance of spintronic devices.