Magnetodielectric effect in a metamaterial consisting of xerogel with embedded epsilon-Fe2O3 iron oxide nanoparticles

Dubrovskiy, A. A.; Balaev, D. A.; Krasikov, A. A.; Yakushhkin, S. S.; Kirillov, V. L.; Martyanov, O. N. Source: SOLID STATE COMMUNICATIONS, 289 27-29; 10.1016/j.ssc.2018.11.020 FEB 2019

The ε-Fe2O3 iron oxide is a fairly rare polymorphic modification, which only exists in the form of nanoparticles embedded, as a rule, into a silica gel matrix. This magnetically ordered iron oxide, which exhibits a significant room-temperature coercivity, is a ferroelectric; therefore, the magnetoelectric and magnetodielectric properties of this material evoke keen interest. In this work, we investigate the magnetodielectric (MD) effect in a metamaterial consisting of xerogel SiO2 with embedded ε-Fe2O3 nanoparticles 9 nm in size on average in a concentration of 20 mass.%. This bulk material exhibits the MD effect in a wide temperature range. The temperature behavior of the permittivity is related to the magnetic state of the ε-Fe2O3 oxide, which undergoes the magnetic transition from the magnetically hard to magnetically soft phase in the temperature range of 80–150 K, indicating the interplay of the ε-Fe2O3 magnetic and charge subsystems.