| Summary: | This work reports the fabrication of zinc ferrite-copper sulphide (ZnFe _2 O _4 /Cu _2 S) 3D heterostructures and subsequent investigation of the spectroscopic behaviour of various electrical parameters like conductivity, impedance and dielectric loss. The study reveals a non-monotonic behaviour of the real component of impedance (Z’), while the imaginary component of impedance (Z’) exhibits a temperature-dependent relaxation frequency, with an estimated activation energy ( E _a ) of 220.13 meV. The dc conductivity ( σ _dc ) measurements reveal the semiconducting nature of the sample and a transition from a ferrimagnetic to a paramagnetic behaviour is reported at the Curie temperature of 327 K. In case of ac conductivity ( σ _ac ), Jonscher’s power law σ _ac = Aω ^n is followed and the exponent n is found to lie in the range 0.679–0.735 at different temperatures, which is best fitted into a polynomial of degree six. The temperature variation of n is suggestive of the overlapping large polaron tunnelling (OLPT) model. Further, ac activation energy ( E _ac ) is also calculated, which is found to be smaller than the dc activation energy ( E _dc ), indicating electron hopping between Fe ^3+ and Fe ^2+ ions. The numerically computed staying time (τ) of electrons in Fe ^3+ /Fe ^2+ ionic sites varies with frequency as well as with temperature, ranging from 10 ^−6 s to 10 ^−19 s. A significant decrease in dielectric loss (tan δ ) to the tune of 99% (from 75 at ∼100 Hz to 0.89 at ∼1 MHz) is reported at room temperature. In the present scenario, when smart materials like spinel ferrites have garnered significant attention for their promising magnetic and electric properties, our studies of the ZnFe _2 O _4 /Cu _2 S 3D heterostructures may provide immense possibilities for tailored applications in various electromagnetic applications.
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