Magnetoelectric coupling driven dielectric anomaly in non-polar system SeCuO3

The non-polar material SeCuO3, which contains Cu2+ with S=1/2S=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.