An insightful observation concerning the effects of co-doping with Zn and Sn on the magnetic and non-linear optical response of CdO thin films

Abstract

In this work, we have investigated the doping effects Zn and Sn on nonlinear optical response and magnetic response of CdO thin films prepared by cost-effective spray pyrolysis method. The optical efficiency was determined from the optical absorbance, transmittance, and linear refractive index. Dielectric parameters were calculated and found to be increased with increasing wavelength and co-doping elements. Dielectric loss decreased with increasing energy level. Uv–vis absorbance spectra were utilized to obtain band gap and were found to be in the order of ∼2.42–2.50 eV. A noticeable improvement was found in nonlinear optical parameters for (Zn + Sn) co-doped CdO lattice, where ${\chi }^{\left(1\right)}$ was estimated to be around $0.072-0.125$ esu, ${\chi }^{\left(3\right)}$ ∼ $\left({-5.65\times 10}^{-18}\right)-{4.17\times 10}^{-14}$ esu, and $N^{\left(2\right)}$ ∼$\left({-2.12\times 10}^{-16}\right)-{9.83\times 10}^{-13}$ esu; respectively. The dispersion of refractive index was analyzed in terms of Wemple–DiDomenico (WDD) single oscillator model. The oscillator parameters $(E_o,E_d,M_{-1}$, $M_{-3})$ were calculated and discussed. The nonlinear refractive index of the (Zn + Sn) co-doped CdO thin films was calculated and displayed a correlation with the linear refractive index. The effective oscillator energy ($E_o$) increased with concentration of doping elements (from 4.86 eV to 5 eV) similar to optical band gap and optical moments ($M_{-1}$ and $M_{-3}$) were found to be decreased with increasing concentration of Sn co-doping. Again, optical conductivity was found to be increased with Zn-doping and Sn co-doping concentration. From the magnetic investigation it was found that paramagnetic CdO lattice transformed to ferromagnetic lattice after co-doping because of magnetic interactions among the dopant atoms. All these results comprehend that (Zn + Sn) co-doping elements improved the nonlinear properties of CdO thin films.