Dielectric Constant, Exchange Bias, and Magnetodielectric Effect in CrO2/Cr2O3 Nanostructures

The magnetodielectric effect has attracted considerable attention due to its intriguing physics and potential engineering applications in modern data storage, sensors, gyrators, and other novel low power electronic applications. Here, we investigate the dielectric behavior, exchange bias coupling, and magnetodielectric effect in nano-scaled CrO2/Cr2O3 core-shell structures. Importantly, our experiments have revealed interesting results whereupon the magnetodielectric effect and exchange bias coupling are strongly correlated in ferromagnetic and antiferromagnetic structures. It is notable that the magnetodielectric effect at room temperature can be enhanced from 1 to 3.5% with exchange bias coupling. Thus, the magnetodielectric effect is enhanced by as much as 250% with the assistance of exchange bias coupling. Results are interpreted here in terms of a spin-dependent transport model.