Influence of dilute doping of Co on structural and magnetic properties of ZnO

Co doped ZnO at dilute concentrations were synthesized using low temperature co-precipitation method. XRD measurements indicates the hexagonal wurtzite structure with P63mc phase group. Also, the impurity phases related to Co ions were absent. Further, Williamson-Hall (W-H) analysis was employed to understand the peak broadening observed upon dilute doping of Co ions in ZnO. Presence of anisotropic strain in the lattice observed from W-H analysis indicates the formation of defect structures. These defects were then confirmed from the magnetic measurements which indicates the direct involvement of Co ions in the formation of oxygen vacancies and controlling the observed room temperature ferromagnetism.