Fig. 2: Electrical response and defect generation modified by the varying configurational entropy.
From: Colossal permittivity in high-entropy CaTiO3 ceramics by chemical bonding engineering
a The complex impedance spectra of CTO-based ceramics measured at 500 °C. Inset: the equivalent circuit model, consisting of two sets of parallel combinations of a resistor and a constant phase element (CPE), representing grain (Rg, CPEg) and grain boundary (Rgb, CPEgb) response. b Fitting results of the grain (Eg) and grain boundary (Egb) activation energies of CTO-based ceramics. c TSDC curves of CTO-based ceramics tested under a polarization voltage (Ep) of 100 V/mm and a polarization temperature (Tp) of 200 °C. Inset: detailed variation in the low depolarization current density region. d TSDC curves of the NSCST ceramic (Tp = 200 °C, Ep = 100–200 V/mm). Inset: magnified view of Peak 1. e The imaginary part of the electric modulus (M″) as a function of frequency for the NSCST ceramic. Inset: fitted activation energy (U) of the detected relaxation peaks circled by the dashed line. f TGA results of CT, CST, and NSCST, indicating the difference in weight loss degree (Δ) between CT and NSCST. g The Ti K-edge XANES spectra of CT, CST, and NSCST. Inset: enlarged view showing the absorption-edge position variation. h, i XPS O 1s spectra of CT (h) and NSCST (i).
