Magnetoelectric coupling driven dielectric anomaly in non-polar system SeCuO _3

摘要

The non-polar material SeCuO _3, which contains Cu ~2 with S=1/2 spin and Se ~4, has a highly distorted perovskite structure due to the small radii of Se ~4 cations. The dielectric constant displays a critical decrease at 25 K, at which temperature the ferromagnetic ordering of the Cu ~2 spin appears, suggesting a strong coupling between the magnetic and dielectric properties. Studies on SeCuO _3 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 SeCuO _3 are quantitative agreement with experimental results.