Dielectric properties of chromium-based low entropy, medium entropy, and high entropy spinel oxides

Entropy stabilizes oxides, a new area of materials research promises special qualities because of their configurational entropy. In this work, we studied chromium-based spinel oxides with different compositional entropies from low entropy $\left({\text{Ni}}_{0.5}{\text{Mn}}_{0.5}\right){\text{Cr}}_2{\text{O}}_4$ to high entropy oxides $\left({\text{Ni}}_{0.2}{\text{Mn}}_{0.2}{\text{Co}}_{0.2}{\text{Cu}}_{0.2}{\text{Zn}}_{0.2}\right){\text{Cr}}_2{\text{O}}_4$ systems to explore their microstructural, dielectric, and electrical characteristics. The XRD analysis reveals that with increasing entropy, no systematic trend is observed in crystallite size, microstrain, or dislocation density, indicating a complex structural evolution. The non-linear dielectric behavior of chromium-based spinel oxides has been demonstrated through an analysis of the real dielectric constant and tangent loss by the modified Debye model. This study reveals that the dielectric properties concurrently enhance as configurational entropy increases systematically from low to high in chromium-based oxides. The high entropy sample shows better dielectric constants and reduced tangent loss, which can be ascribed to the combined effects of multi-element effects and greater ion mobility. The interfacial polarization hypothesis proposed by Maxwell and Wagner has been utilized to comprehend the behavior of dielectric constants. The detailed investigation of dielectric properties might be beneficial for electrical and electrochemical applications.