Observation of structural, optical, electrical and magnetic properties of ternary copper-doped CeO2/GO/SrTiO3 nanocomposites

Abstract

A ternary system involving copper-substituted ceria (Cu:CeO2)0.95−y(GO)y(SrTiO3)0.05 nanocomposite where the GO concentration (y) is varied between 0.15 and 0.30. The innovation of this work lies in the purposeful assembly of the nanocomposite using a grinding method, which was optimized through the individual fabrication of Cu-doped CeO2 with different CuO concentrations. In the first, Cu-doped CeO2 with various CuO concentrations (x = 0.0, 0.05, 0.1, 0.2, and 0.3) was first individually fabricated based on a sol–gel auto-combustion strategy to optimize the best ratio. The XRD profiles confirm the successful fabrication of cubic cerium (IV) oxide CeO2 using glycine as a fuel at an annealing temperature of 400 °C for 2 h. AC conductivity was investigated for both Cu-doped CeO2 and the ternary nanocomposite over a wide frequency range (10–1 to 107 Hz) at room temperature. The conductivity showed lower values for CeO2 doped with 0.05, 0.2, and 0.3 wt% CuO, whereas it showed its maximum values upon doping with 0.1 wt% CuO. Interestingly, the conductivity of graphene oxide–doped CeO2 was 103 times higher than that of pure CeO2, i.e., it increased from 1.7 × 10–6 to 2 × 10–3 S/cm. The magnetic-field dependence of MS of the ternary Cu-doped CeO2/GO/SrTiO3 nanocomposites showed a systematic increase in MS as the Cu2+ ion content increased. This strengthens the ferromagnetism in our samples as Cu2+ ion content increases.