Magnetoelectric coupling driven dielectric anomaly in non-polar system SeCuO3

The non-polar material SeCuO₃, which contains Cu²⁺ with S=1/2$S=1/2$ spin and Se⁴⁺, has a highly distorted perovskite structure due to the small radii of Se⁴⁺ cations. The dielectric constant displays a critical decrease at 25 K, at which temperature the ferromagnetic ordering of the Cu²⁺ spin appears, suggesting a strong coupling between the magnetic and dielectric properties. Studies on SeCuO₃ show that the magnetic and electrical subsystems reciprocally correlate via the hybridization of sp and pd. We conclude that the spin–pair correlation along the b-axis plays a significant role in the decrease of the dielectric constant around the magnetic transition temperature via the magnetoelectric coupling, and successfully explain the dielectric anomaly. The obtained dielectric constant and the magnetocapacitance for SeCuO₃ are quantitative agreement with experimental results.