Enhanced optical, dielectric and ferromagnetic properties in ZnO/M nanocomposites for advanced device applications

ZnO/M nanocomposites incorporating transition metal oxides (M = CuO, Fe₂O₃, Mn₃O₄) demonstrate significantly tuned functional properties relevant for advanced device applications. Photoluminescence studies reveal modified optical behavior, with all composites showing reduced emission intensity. Blue shifts for Fe₂O₃ and Mn₃O₄ composites contrast with a violet shift observed in the CuO composite, reflected in an I_B/I_V ratio of 1.023, 1.018, and 0.936, respectively. Electrical characterization shows substantially enhanced performance in nanocomposites. Higher dielectric constants and improved AC conductivity values are recorded, particularly in ZnO/CuO samples. Relaxation dynamics shift toward higher frequencies, with peaks in the electric modulus (M'') observed at 1860 kHz for ZnO/CuO, compared to 100 kHz for pure ZnO, and Cole-Cole analysis confirming non-Debye type behavior. Unique electrical transport emerges in ZnO/Fe₂O₃, where two successive semicircles in impedance plots suggest complex charge conduction pathways with grain boundary resistance reaching 185 MΩ. Magnetic properties show notable enhancement through composite formation. All nanocomposites exhibit strengthened ferromagnetic character compared to pure ZnO, with saturation magnetization increasing progressively from 0.035 emu/g (ZnO) through 0.039 (ZnO/CuO), 0.050 (ZnO/Fe₂O₃), to 0.058 emu/g (ZnO/Mn₃O₄). The materials demonstrate hard magnetic behavior with coercivity values of 70-80 Oe and double exchange interactions dominating, supported by an effective magnetic anisotropy (K_eff) increasing from 148 emu·Oe/g for ZnO to 432 emu·Oe/g for ZnO/Mn₃O₄. These simultaneous improvements across optical, electrical, and magnetic domains position ZnO/M nanocomposites as promising candidates for emerging technologies including spintronic devices, high-frequency telecommunications, and advanced energy storage systems.