Magneto-dielectric behavior of electrodeposited FeAl₂O₄ nanostructures

Spinel class of materials, with significant magnetodielectric (MD) coupling, has potential for multifunctional devices/applications. Present research work discusses and correlates the structural, dielectric, magnetic, and MD response of iron aluminum oxide (FeAl₂O₄) nanostructures with preparation conditions. To prepare iron aluminum oxide nanostructures, an application oriented technique, i.e. electrodeposition, is used. A series of samples is deposited by varying oxidation time as 0, 5, 10, 15, 20, 25, and 30 min; deposition time used is 20 min under magnetic stirring. Structural analysis reveals mixed phases at lower oxidation condition (5–10 min). Restructuring is observed at 15 min oxidation that results in phase purity at 20 min. Another phase shift, resulting in the formation of mixed phases, is observed at oxidation time of 25–30 min. SEM results show preparation condition-dependent surface morphology of iron aluminum oxide nanostructures without using the template, i.e. core–shell, dendrites, hexagonal, cubic, and octahedral grains. Phase purity (FeAl₂O₄), observed at 20 min of oxidation time, shows high value of saturation magnetization (46.07 emu/cm³). Anomalous dielectric behavior is observed for iron aluminum oxide nanostructures due to resonance phenomenon. Magnetic–dielectric (MD) coupling is observed by MD measurements. MD value of ~ 7% is observed for the sampled prepared with 20 min oxidation time. Stirring mediated electrodeposited iron aluminum oxide nanostructures followed by in situ oxidation is one of its kind study that leads to the formation of spinel structure with enhanced MD coupling useful for advanced electronic applications.