Novel optical properties and induced magnetic moments in Ru-doped hybrid improper ferroelectric Ca3Ti2O7
Xingxing Wu, Shouyu Wang, W. Wong‐Ng, Qiang Gu, Yao Jiang, Chao Wang, Shuang Ma, Weifang Liu
Abstract
Abstract Hybrid improper ferroelectric Ca 3 Ti 2 O 7 and Ca 3 Ti 19 Ru 0.1 O 7 ceramics were successfully synthesized by conventional solid-state reaction method. Two strongest diffraction peaks located around 2 θ = 33° shifted towards the lower angle region with Ru substitution, reflecting structure variation. Grain growth and higher oxygen vacancy concentration after doping resulted in a reduction in the coercive field about 20 kV/cm. Optical bandgap estimated by UV-vis diffuse reflectance (DR) spectrum and X-ray photoelectron spectroscopy (XPS) valence band spectra showed a decreasing trend due to the existence of impurity energy level upon Ru doping, which was consistent with the results of first-principles calculations. The origin of the unexpected induced magnetic moments in Ru-dope Ca 3 Ti 2 O 7 is also discussed.