Crystallography, impurities and magnetic properties of Mn - Doped ZnO nanoparticles prepared by coprecipitation method

Introduction of Mn²⁺ ions into ZnO in the form of Zn_(1-x)Mn_xO (0.00≤x≤0.25) has been done by means of coprecipitation method at low temperature using Zn(CH₃COO)₂2H₂O, Mn(CH₃COO)₂4H₂O, HCl, and NH4OH as starting materials. The XRD analysis showed that the produced Zn_(1-x)MnxO (0.00≤x≤0.09) samples were crystallized in single phase of wurtzite with hexagonal structures. Besides the wurtzite, the presence of the secondary phase of hetaerolite ZnMn2O4 with tetragonal structures was detected in the samples having 0.10≤x≤0.25. The nanometer-sized Zn_(1-x)Mn_xO crystals obtained from XRD analysis were well confirmed by SEM and TEM images. The electron diffraction data showed that the secondary phase formed even for 0.01 and 0.10 Mn-doping samples were ZnMn₂O₄ and MnO₂. The VSM data indicate that the paramagnetic properties of Mn doping occurred at 0.00=x=0.06 and 0.10=x=0.25 as well as superparamagnetic properties occur in Mn doping 0.07≤x≤0.09. The most interesting fact in this study was the formation of secondary phases in all Mn-doped ZnO samples, even for the smallest x of 0.01.