Effect of (Li, Mn) co-doping on structural, optical and magnetic properties of chunk-shaped nano ZnO

•Chunk-shaped nano ZnO synthesized by varying Li and Mn doping concentrations.•The growth mechanism was discussed for chunk-shaped morphologies.•Undoped and Li doped CSNS ZnO exhibit weak ferromagnetic behavior with diamagnetism.•Room temperature ferromagnetism observed for Mn doped and Li/Mn co-doped CSNS ZnO.•Verdet constants and magneto-optic properties were measured from Faraday Effect method. Chunk shaped ZnO nanostructures (CSNS) simultaneously doped with Li and Mn for varying Li/Mn concentrations have been synthesized using wet-chemical method. Their crystal structural, optical and magnetic properties at room temperature (RT) were then investigated, which revealed that all the samples have a single phase with the wurtzite structure. Undoped and co-doped ZnO chunk-shape structures has been demonstrated by transmission electron microscope (TEM). The Mn/Li incorporation also creates more lattice defects and disorders, which influence directly characteristic photoluminescence (PL), FTIR and UV–vis spectra of Zn1−x−yMnyLixO CSNS. Where green emission due to concentration of defects is seen. Magnetic measurements by VSM and the ferro fluid of synthesized nano ZnO by Faraday optical rotation for various concentration of Mn and Li in nano ZnO are done. Change of magnetic and magneto-optic (MO) properties due to Mn and Li ions are discussed in detail.