Advancements in multiferroic, dielectric, and impedance properties of copper–yttrium co-doped cobalt ferrite for hydroelectric cell applications

Abstract

This paper explores yttrium and copper co-doped cobalt ferrite [Co1−x Cu x Fe1.85Y0.15O4] synthesized via the sol–gel auto-combustion route (0.0 ⩽ x ⩽ 0.08). Investigating the impact of co-dopants on CoFe2O4, the study reveals altered cation distribution affecting the structure, multiferroic, and electrical properties. X-ray diffraction studies show nanocrystalline co-doped cobalt ferrites with lattice expansion and smaller grains due to Cu–Y co-doping. Fourier transform infrared spectroscopy confirms inverse spinel family classification with tetrahedral lattice shrinkage. Field emission scanning electron microscopy indicates a grain size of approximately 0.12 μm. Ferroelectric analysis reveals a peak saturation polarization of 23.42 μC cm−2 for 8% copper doping, attributed to increased Fe3+ ions at tetrahedral sites. Saturation magnetization peaks at 54.4706 emu g−1 for 2% Cu2+ ion substitution [Co0.98Cu0.02Fe1.85Y0.15O4] and decreases to 37.09 emu g−1 for 4% Cu substitution due to irregular iron atom distribution at tetrahedral sites. Dielectric studies uncover Maxwell–Wagner polarization and high resistance in grain and grain boundaries using impedance spectroscopy. Fabricated hydroelectric cells exhibit improved ionic diffusion, suggesting their use in potential hydroelectric cell applications.