Size and grain morphology dependent magnetic behaviour of Co-doped ZnO

We have carried out a comparative study of structural, microstructural and magnetic properties of the two sets of Co-doped ZnO samples synthesized using solid state reaction and sol–gel method. Rietveld refinement of the X-ray diffraction data reveals single phase hexagonal wurtzite structure for all the samples, while the tunnelling electron microscopy measurements show the presence of nano-phase in the sol–gel grown Co-doped ZnO samples. It is found that, the microstructure strongly depends on the synthesis method adopted. Samples with higher Co-concentration synthesized by SSR route exhibit antiferromagnetism while SG grown Co-doped ZnO samples exhibit weak ferromagnetic behaviour. Improved magnetic phase in the SG grown samples has been attributed to the grain morphology.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Structure and magnetic studies on Co-doped ZnO. ► Synthesis method dependent comparison of magnetic properties. ► Grain size and morphology affect the magnetic properties of Co-doped ZnO.